pg

package module
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 Go to latest Published: Dec 14, 2024 License: BSD-2-Clause Imports: 24 Imported by: 1,018

README

PostgreSQL client and ORM for Golang

Maintenance mode

go-pg is in a maintenance mode and only critical issues are addressed. New development happens in Bun repo which offers similar functionality but works with PostgreSQL, MySQL, MariaDB, and SQLite.

Golang ORM

Go PkgGoDev Documentation Chat

Tutorials

Ecosystem

Features

Installation

go-pg supports 2 last Go versions and requires a Go version with modules support. So make sure to initialize a Go module:

go mod init github.com/my/repo

And then install go-pg (note v10 in the import; omitting it is a popular mistake):

go get github.com/go-pg/pg/v10

Quickstart

package pg_test

import (
    "fmt"

    "github.com/go-pg/pg/v10"
    "github.com/go-pg/pg/v10/orm"
)

type User struct {
    Id     int64
    Name   string
    Emails []string
}

func (u User) String() string {
    return fmt.Sprintf("User<%d %s %v>", u.Id, u.Name, u.Emails)
}

type Story struct {
    Id       int64
    Title    string
    AuthorId int64
    Author   *User `pg:"rel:has-one"`
}

func (s Story) String() string {
    return fmt.Sprintf("Story<%d %s %s>", s.Id, s.Title, s.Author)
}

func ExampleDB_Model() {
    db := pg.Connect(&pg.Options{
        User: "postgres",
    })
    defer db.Close()

    err := createSchema(db)
    if err != nil {
        panic(err)
    }

    user1 := &User{
        Name:   "admin",
        Emails: []string{"admin1@admin", "admin2@admin"},
    }
    _, err = db.Model(user1).Insert()
    if err != nil {
        panic(err)
    }

    _, err = db.Model(&User{
        Name:   "root",
        Emails: []string{"root1@root", "root2@root"},
    }).Insert()
    if err != nil {
        panic(err)
    }

    story1 := &Story{
        Title:    "Cool story",
        AuthorId: user1.Id,
    }
    _, err = db.Model(story1).Insert()
    if err != nil {
        panic(err)
    }

    // Select user by primary key.
    user := &User{Id: user1.Id}
    err = db.Model(user).WherePK().Select()
    if err != nil {
        panic(err)
    }

    // Select all users.
    var users []User
    err = db.Model(&users).Select()
    if err != nil {
        panic(err)
    }

    // Select story and associated author in one query.
    story := new(Story)
    err = db.Model(story).
        Relation("Author").
        Where("story.id = ?", story1.Id).
        Select()
    if err != nil {
        panic(err)
    }

    fmt.Println(user)
    fmt.Println(users)
    fmt.Println(story)
    // Output: User<1 admin [admin1@admin admin2@admin]>
    // [User<1 admin [admin1@admin admin2@admin]> User<2 root [root1@root root2@root]>]
    // Story<1 Cool story User<1 admin [admin1@admin admin2@admin]>>
}

// createSchema creates database schema for User and Story models.
func createSchema(db *pg.DB) error {
    models := []interface{}{
        (*User)(nil),
        (*Story)(nil),
    }

    for _, model := range models {
        err := db.Model(model).CreateTable(&orm.CreateTableOptions{
            Temp: true,
        })
        if err != nil {
            return err
        }
    }
    return nil
}

See also

Documentation

Overview

pg provides PostgreSQL client.

Example (Placeholders)

go-pg recognizes `?` in queries as placeholders and replaces them with parameters when queries are executed. `?` can be escaped with backslash. Parameters are escaped before replacing according to PostgreSQL rules. Specifically:

  • all parameters are properly quoted against SQL injections;
  • null byte is removed;
  • JSON/JSONB gets `\u0000` escaped as `\\u0000`.
package main

import (
	"fmt"

	"github.com/go-pg/pg/v10"
)

type Params struct {
	X int
	Y int
}

func (p *Params) Sum() int {
	return p.X + p.Y
}

// go-pg recognizes `?` in queries as placeholders and replaces them
// with parameters when queries are executed. `?` can be escaped with backslash.
// Parameters are escaped before replacing according to PostgreSQL rules.
// Specifically:
//   - all parameters are properly quoted against SQL injections;
//   - null byte is removed;
//   - JSON/JSONB gets `\u0000` escaped as `\\u0000`.
func main() {
	var num int

	// Simple params.
	_, err := pgdb.Query(pg.Scan(&num), "SELECT ?", 42)
	if err != nil {
		panic(err)
	}
	fmt.Println("simple:", num)

	// Indexed params.
	_, err = pgdb.Query(pg.Scan(&num), "SELECT ?0 + ?0", 1)
	if err != nil {
		panic(err)
	}
	fmt.Println("indexed:", num)

	// Named params.
	params := &Params{
		X: 1,
		Y: 1,
	}
	_, err = pgdb.Query(pg.Scan(&num), "SELECT ?x + ?y + ?Sum", params)
	if err != nil {
		panic(err)
	}
	fmt.Println("named:", num)

	// Global params.
	_, err = pgdb.WithParam("z", 1).Query(pg.Scan(&num), "SELECT ?x + ?y + ?z", params)
	if err != nil {
		panic(err)
	}
	fmt.Println("global:", num)

	// Model params.
	var tableName, tableAlias, tableColumns, columns string
	_, err = pgdb.Model(&Params{}).Query(
		pg.Scan(&tableName, &tableAlias, &tableColumns, &columns),
		"SELECT '?TableName', '?TableAlias', '?TableColumns', '?Columns'",
	)
	if err != nil {
		panic(err)
	}
	fmt.Println("table name:", tableName)
	fmt.Println("table alias:", tableAlias)
	fmt.Println("table columns:", tableColumns)
	fmt.Println("columns:", columns)

}

Output:

simple: 42
indexed: 2
named: 4
global: 3
table name: "params"
table alias: "params"
table columns: "params"."x", "params"."y"
columns: "x", "y"

Index

Examples

Constants

This section is empty.

Variables

View Source 
var Discard orm.Discard

Discard is used with Query and QueryOne to discard rows.

View Source 
var ErrMultiRows = internal.ErrMultiRows

ErrMultiRows is returned by QueryOne and ExecOne when query returned multiple rows but exactly one row is expected.

View Source 
var ErrNoRows = internal.ErrNoRows

ErrNoRows is returned by QueryOne and ExecOne when query returned zero rows but at least one row is expected.

View Source 
var ErrTxDone = errors.New("pg: transaction has already been committed or rolled back")

ErrTxDone is returned by any operation that is performed on a transaction that has already been committed or rolled back.

Functions

func Array 

func Array(v interface{}) *types.Array

Array accepts a slice and returns a wrapper for working with PostgreSQL array data type.

For struct fields you can use array tag: 

Emails  []string `pg:",array"`
Example 
src := []string{"one@example.com", "two@example.com"}
var dst []string
_, err := pgdb.QueryOne(pg.Scan(pg.Array(&dst)), `SELECT ?`, pg.Array(src))
panicIf(err)
fmt.Println(dst)

Output:

[one@example.com two@example.com]

func Hstore 

func Hstore(v interface{}) *types.Hstore

Hstore accepts a map and returns a wrapper for working with hstore data type. Supported map types are:

  • map[string]string

For struct fields you can use hstore tag: 

Attrs map[string]string `pg:",hstore"`
Example 
src := map[string]string{"hello": "world"}
var dst map[string]string
_, err := pgdb.QueryOne(pg.Scan(pg.Hstore(&dst)), `SELECT ?`, pg.Hstore(src))
if err != nil {
	panic(err)
}
fmt.Println(dst)

Output:

map[hello:world]

func In 

func In(slice interface{}) types.ValueAppender

In accepts a slice and returns a wrapper that can be used with PostgreSQL IN operator: 

Where("id IN (?)", pg.In([]int{1, 2, 3, 4}))

produces 

WHERE id IN (1, 2, 3, 4)

func InMulti 

func InMulti(values ...interface{}) types.ValueAppender

InMulti accepts multiple values and returns a wrapper that can be used with PostgreSQL IN operator: 

Where("(id1, id2) IN (?)", pg.InMulti([]int{1, 2}, []int{3, 4}))

produces 

WHERE (id1, id2) IN ((1, 2), (3, 4))

func SafeQuery 

func SafeQuery(query string, params ...interface{}) *orm.SafeQueryAppender

SafeQuery replaces any placeholders found in the query.

func Scan 

func Scan(values ...interface{}) orm.ColumnScanner

Scan returns ColumnScanner that copies the columns in the row into the values.

Example 
var s1, s2 string
_, err := pgdb.QueryOne(pg.Scan(&s1, &s2), `SELECT ?, ?`, "foo", "bar")
panicIf(err)
fmt.Println(s1, s2)

Output:

foo bar

func SetLogger 

func SetLogger(logger internal.Logging)

SetLogger sets the logger to the given one.

func Version added in v10.10.4 

func Version() string

Version is the current release version.

Types

type AfterDeleteHook 

type AfterDeleteHook = orm.AfterDeleteHook

type AfterInsertHook 

type AfterInsertHook = orm.AfterInsertHook

type AfterScanHook 

type AfterScanHook = orm.AfterScanHook

type AfterSelectHook 

type AfterSelectHook = orm.AfterSelectHook

type AfterUpdateHook 

type AfterUpdateHook = orm.AfterUpdateHook

type BeforeDeleteHook 

type BeforeDeleteHook = orm.BeforeDeleteHook

type BeforeInsertHook 

type BeforeInsertHook = orm.BeforeInsertHook

type BeforeScanHook 

type BeforeScanHook = orm.BeforeScanHook

type BeforeUpdateHook 

type BeforeUpdateHook = orm.BeforeUpdateHook

type Conn 

type Conn struct {
	// contains filtered or unexported fields
}

Conn represents a single database connection rather than a pool of database connections. Prefer running queries from DB unless there is a specific need for a continuous single database connection.

A Conn must call Close to return the connection to the database pool and may do so concurrently with a running query.

After a call to Close, all operations on the connection fail.

func (Conn) AddQueryHook 

func (db Conn) AddQueryHook(hook QueryHook)

AddQueryHook adds a hook into query processing.

func (Conn) Begin 

func (db Conn) Begin() (*Tx, error)

Begin starts a transaction. Most callers should use RunInTransaction instead.

func (Conn) BeginContext 

func (db Conn) BeginContext(ctx context.Context) (*Tx, error)

func (Conn) Close 

func (db Conn) Close() error

Close closes the database client, releasing any open resources.

It is rare to Close a DB, as the DB handle is meant to be long-lived and shared between many goroutines.

func (*Conn) Context 

func (db *Conn) Context() context.Context

Context returns DB context.

func (Conn) CopyFrom 

func (db Conn) CopyFrom(r io.Reader, query interface{}, params ...interface{}) (res Result, err error)

CopyFrom copies data from reader to a table.

func (Conn) CopyTo 

func (db Conn) CopyTo(w io.Writer, query interface{}, params ...interface{}) (res Result, err error)

CopyTo copies data from a table to writer.

func (Conn) Exec 

func (db Conn) Exec(query interface{}, params ...interface{}) (res Result, err error)

Exec executes a query ignoring returned rows. The params are for any placeholders in the query.

func (Conn) ExecContext 

func (db Conn) ExecContext(c context.Context, query interface{}, params ...interface{}) (Result, error)

func (Conn) ExecOne 

func (db Conn) ExecOne(query interface{}, params ...interface{}) (Result, error)

ExecOne acts like Exec, but query must affect only one row. It returns ErrNoRows error when query returns zero rows or ErrMultiRows when query returns multiple rows.

func (Conn) ExecOneContext 

func (db Conn) ExecOneContext(ctx context.Context, query interface{}, params ...interface{}) (Result, error)

func (Conn) Formatter 

func (db Conn) Formatter() orm.QueryFormatter

func (Conn) Model 

func (db Conn) Model(model ...interface{}) *Query

Model returns new query for the model.

func (Conn) ModelContext 

func (db Conn) ModelContext(c context.Context, model ...interface{}) *Query

func (Conn) Param 

func (db Conn) Param(param string) interface{}

Param returns value for the param.

func (Conn) Ping 

func (db Conn) Ping(ctx context.Context) error

Ping verifies a connection to the database is still alive, establishing a connection if necessary.

func (Conn) PoolStats 

func (db Conn) PoolStats() *PoolStats

PoolStats returns connection pool stats.

func (Conn) Prepare 

func (db Conn) Prepare(q string) (*Stmt, error)

Prepare creates a prepared statement for later queries or executions. Multiple queries or executions may be run concurrently from the returned statement.

func (Conn) Query 

func (db Conn) Query(model, query interface{}, params ...interface{}) (res Result, err error)

Query executes a query that returns rows, typically a SELECT. The params are for any placeholders in the query.

func (Conn) QueryContext 

func (db Conn) QueryContext(c context.Context, model, query interface{}, params ...interface{}) (Result, error)

func (Conn) QueryOne 

func (db Conn) QueryOne(model, query interface{}, params ...interface{}) (Result, error)

QueryOne acts like Query, but query must return only one row. It returns ErrNoRows error when query returns zero rows or ErrMultiRows when query returns multiple rows.

func (Conn) QueryOneContext 

func (db Conn) QueryOneContext(
	ctx context.Context, model, query interface{}, params ...interface{},
) (Result, error)

func (Conn) RunInTransaction 

func (db Conn) RunInTransaction(ctx context.Context, fn func(*Tx) error) error

RunInTransaction runs a function in a transaction. If function returns an error transaction is rolled back, otherwise transaction is committed.

func (*Conn) WithContext 

func (db *Conn) WithContext(ctx context.Context) *Conn

WithContext returns a copy of the DB that uses the ctx.

func (*Conn) WithParam 

func (db *Conn) WithParam(param string, value interface{}) *Conn

WithParam returns a copy of the DB that replaces the param with the value in queries.

func (*Conn) WithTimeout 

func (db *Conn) WithTimeout(d time.Duration) *Conn

WithTimeout returns a copy of the DB that uses d as the read/write timeout.

type DB 

type DB struct {
	// contains filtered or unexported fields
}

DB is a database handle representing a pool of zero or more underlying connections. It's safe for concurrent use by multiple goroutines.

Example (ArrayValueScanner) 
var dst MyArrayValueScanner
_, err := pgdb.QueryOne(pg.Scan(pg.Array(&dst)),
	`SELECT array_agg(id) from generate_series(0, 10) AS id`)
panicIf(err)
fmt.Println(dst.sum)

Output:

55
Example (JsonUseNumber) 
type Event struct {
	Id   int
	Data map[string]interface{} `pg:",json_use_number"`
}

db := pg.Connect(pgOptions())
defer db.Close()

err := db.Model((*Event)(nil)).CreateTable(&orm.CreateTableOptions{
	Temp: true,
})
if err != nil {
	panic(err)
}

event := &Event{
	Data: map[string]interface{}{
		"price": 1.23,
	},
}
_, err = db.Model(event).Insert()
if err != nil {
	panic(err)
}

event2 := new(Event)
err = db.Model(event2).Where("id = ?", event.Id).Select()
if err != nil {
	panic(err)
}

// Check that price is decoded as json.Number.
fmt.Printf("%T", event2.Data["price"])

Output:

json.Number

func Connect 

func Connect(opt *Options) *DB

Connect connects to a database using provided options.

The returned DB is safe for concurrent use by multiple goroutines and maintains its own connection pool.

Example 
db := pg.Connect(&pg.Options{
	User:     "postgres",
	Password: "postgres",
	Database: "postgres",
})
defer db.Close()

var n int
_, err := db.QueryOne(pg.Scan(&n), "SELECT 1")
panicIf(err)
fmt.Println(n)

Output:

1

func (DB) AddQueryHook 

func (db DB) AddQueryHook(hook QueryHook)

AddQueryHook adds a hook into query processing.

func (DB) Begin 

func (db DB) Begin() (*Tx, error)

Begin starts a transaction. Most callers should use RunInTransaction instead.

Example 
db := txExample()

incrInTx := func(db *pg.DB) error {
	tx, err := db.Begin()
	if err != nil {
		return err
	}
	// Rollback tx on error.
	defer tx.Rollback()

	var counter int
	_, err = tx.QueryOne(
		pg.Scan(&counter), `SELECT counter FROM tx_test FOR UPDATE`)
	if err != nil {
		return err
	}

	counter++

	_, err = tx.Exec(`UPDATE tx_test SET counter = ?`, counter)
	if err != nil {
		return err
	}

	return tx.Commit()
}

var wg sync.WaitGroup
for i := 0; i < 10; i++ {
	wg.Add(1)
	go func() {
		defer wg.Done()
		err := incrInTx(db)
		panicIf(err)
	}()
}
wg.Wait()

var counter int
_, err := db.QueryOne(pg.Scan(&counter), `SELECT counter FROM tx_test`)
panicIf(err)
fmt.Println(counter)

Output:

10

func (DB) BeginContext 

func (db DB) BeginContext(ctx context.Context) (*Tx, error)

func (DB) Close 

func (db DB) Close() error

Close closes the database client, releasing any open resources.

It is rare to Close a DB, as the DB handle is meant to be long-lived and shared between many goroutines.

func (*DB) Conn 

func (db *DB) Conn() *Conn

Conn returns a single connection from the connection pool. Queries run on the same Conn will be run in the same database session.

Every Conn must be returned to the database pool after use by calling Conn.Close.

func (*DB) Context 

func (db *DB) Context() context.Context

Context returns DB context.

func (DB) CopyFrom 

func (db DB) CopyFrom(r io.Reader, query interface{}, params ...interface{}) (res Result, err error)

CopyFrom copies data from reader to a table.

Example 
_, err := pgdb.Exec(`CREATE TEMP TABLE words(word text, len int)`)
panicIf(err)

r := strings.NewReader("hello,5\nfoo,3\n")
_, err = pgdb.CopyFrom(r, `COPY words FROM STDIN WITH CSV`)
panicIf(err)

var buf bytes.Buffer
_, err = pgdb.CopyTo(&buf, `COPY words TO STDOUT WITH CSV`)
panicIf(err)
fmt.Println(buf.String())

Output:

hello,5
foo,3

func (DB) CopyTo 

func (db DB) CopyTo(w io.Writer, query interface{}, params ...interface{}) (res Result, err error)

CopyTo copies data from a table to writer.

func (DB) Exec 

func (db DB) Exec(query interface{}, params ...interface{}) (res Result, err error)

Exec executes a query ignoring returned rows. The params are for any placeholders in the query.

Example 
res, err := pgdb.Exec(`CREATE TEMP TABLE test()`)
panicIf(err)
fmt.Println(res.RowsAffected())

Output:

-1

func (DB) ExecContext 

func (db DB) ExecContext(c context.Context, query interface{}, params ...interface{}) (Result, error)

func (DB) ExecOne 

func (db DB) ExecOne(query interface{}, params ...interface{}) (Result, error)

ExecOne acts like Exec, but query must affect only one row. It returns ErrNoRows error when query returns zero rows or ErrMultiRows when query returns multiple rows.

func (DB) ExecOneContext 

func (db DB) ExecOneContext(ctx context.Context, query interface{}, params ...interface{}) (Result, error)

func (DB) Formatter 

func (db DB) Formatter() orm.QueryFormatter

func (*DB) Listen 

func (db *DB) Listen(ctx context.Context, channels ...string) *Listener

Listen listens for notifications sent with NOTIFY command.

func (DB) Model 

func (db DB) Model(model ...interface{}) *Query

Model returns new query for the model.

Example 
package main

import (
	"fmt"

	"github.com/go-pg/pg/v10"
	"github.com/go-pg/pg/v10/orm"
)

type User struct {
	Id     int64
	Name   string
	Emails []string
}

func (u User) String() string {
	return fmt.Sprintf("User<%d %s %v>", u.Id, u.Name, u.Emails)
}

type Story struct {
	Id       int64
	Title    string
	AuthorId int64
	Author   *User `pg:"rel:has-one"`
}

func (s Story) String() string {
	return fmt.Sprintf("Story<%d %s %s>", s.Id, s.Title, s.Author)
}

func main() {
	db := pg.Connect(&pg.Options{
		User:     "postgres",
		Password: "postgres",
	})
	defer db.Close()

	err := createSchema(db)
	if err != nil {
		panic(err)
	}

	user1 := &User{
		Name:   "admin",
		Emails: []string{"admin1@admin", "admin2@admin"},
	}
	_, err = db.Model(user1).Insert()
	if err != nil {
		panic(err)
	}

	_, err = db.Model(&User{
		Name:   "root",
		Emails: []string{"root1@root", "root2@root"},
	}).Insert()
	if err != nil {
		panic(err)
	}

	story1 := &Story{
		Title:    "Cool story",
		AuthorId: user1.Id,
	}
	_, err = db.Model(story1).Insert()
	if err != nil {
		panic(err)
	}

	// Select user by primary key.
	user := &User{Id: user1.Id}
	err = db.Model(user).WherePK().Select()
	if err != nil {
		panic(err)
	}

	// Select all users.
	var users []User
	err = db.Model(&users).Select()
	if err != nil {
		panic(err)
	}

	// Select story and associated author in one query.
	story := new(Story)
	err = db.Model(story).
		Relation("Author").
		Where("story.id = ?", story1.Id).
		Select()
	if err != nil {
		panic(err)
	}

	fmt.Println(user)
	fmt.Println(users)
	fmt.Println(story)
}

// createSchema creates database schema for User and Story models.
func createSchema(db *pg.DB) error {
	models := []interface{}{
		(*User)(nil),
		(*Story)(nil),
	}

	for _, model := range models {
		err := db.Model(model).CreateTable(&orm.CreateTableOptions{
			Temp: true,
		})
		if err != nil {
			return err
		}
	}
	return nil
}

Output:

User<1 admin [admin1@admin admin2@admin]>
[User<1 admin [admin1@admin admin2@admin]> User<2 root [root1@root root2@root]>]
Story<1 Cool story User<1 admin [admin1@admin admin2@admin]>>
Example (BelongsTo) 
// Profile belongs to User.
type Profile struct {
	Id     int
	Lang   string
	UserId int
}

type User struct {
	Id      int
	Name    string
	Profile *Profile `pg:"rel:belongs-to"`
}

db := connect()
defer db.Close()

qs := []string{
	"CREATE TEMP TABLE users (id int, name text)",
	"CREATE TEMP TABLE profiles (id int, lang text, user_id int)",
	"INSERT INTO users VALUES (1, 'user 1'), (2, 'user 2')",
	"INSERT INTO profiles VALUES (1, 'en', 1), (2, 'ru', 2)",
}
for _, q := range qs {
	_, err := db.Exec(q)
	if err != nil {
		panic(err)
	}
}

// Select users joining their profiles with following query:
//
// SELECT
//   "user".*,
//   "profile"."id" AS "profile__id",
//   "profile"."lang" AS "profile__lang",
//   "profile"."user_id" AS "profile__user_id"
// FROM "users" AS "user"
// LEFT JOIN "profiles" AS "profile" ON "profile"."user_id" = "user"."id"

var users []User
err := db.Model(&users).
	Column("user.*").
	Relation("Profile").
	Select()
if err != nil {
	panic(err)
}

fmt.Println(len(users), "results")
fmt.Println(users[0].Id, users[0].Name, users[0].Profile)
fmt.Println(users[1].Id, users[1].Name, users[1].Profile)

Output:

2 results
1 user 1 &{1 en 1}
2 user 2 &{2 ru 2}
Example (BulkDelete) 
db := modelDB()

var books []Book
err := db.Model(&books).Select()
if err != nil {
	panic(err)
}

res, err := db.Model(&books).Delete()
if err != nil {
	panic(err)
}
fmt.Println("deleted", res.RowsAffected())

count, err := db.Model((*Book)(nil)).Count()
if err != nil {
	panic(err)
}
fmt.Println("left", count)

Output:

deleted 3
left 0
Example (BulkInsert) 
db := modelDB()

book1 := &Book{
	Title: "new book 1",
}
book2 := &Book{
	Title: "new book 2",
}
_, err := db.Model(book1, book2).Insert()
if err != nil {
	panic(err)
}
fmt.Println(book1, book2)

Output:

Book<Id=4 Title="new book 1"> Book<Id=5 Title="new book 2">
Example (BulkInsertSlice) 
db := modelDB()

books := []Book{{
	Title: "new book 1",
}, {
	Title: "new book 2",
}}
_, err := db.Model(&books).Insert()
if err != nil {
	panic(err)
}
fmt.Println(books)

Output:

[Book<Id=4 Title="new book 1"> Book<Id=5 Title="new book 2">]
Example (BulkUpdate) 
db := modelDB()

book1 := &Book{
	ID:        1,
	Title:     "updated book 1",
	UpdatedAt: time.Now(),
}
book2 := &Book{
	ID:        2,
	Title:     "updated book 2",
	UpdatedAt: time.Now(),
}

// UPDATE "books" AS "book"
// SET "title" = _data."title"
// FROM (VALUES ('updated book 1', 1), ('updated book 2', 2)) AS _data("title", "id")
// WHERE "book"."id" = _data."id"
_, err := db.Model(book1, book2).Column("title", "updated_at").Update()
if err != nil {
	panic(err)
}

var books []Book
err = db.Model(&books).Order("id").Select()
if err != nil {
	panic(err)
}

fmt.Println(books)

Output:

[Book<Id=1 Title="updated book 1"> Book<Id=2 Title="updated book 2"> Book<Id=3 Title="book 3">]
Example (BulkUpdateSlice) 
db := modelDB()

books := []Book{{
	ID:        1,
	Title:     "updated book 1",
	UpdatedAt: time.Now(),
}, {
	ID:        2,
	Title:     "updated book 2",
	UpdatedAt: time.Now(),
}}

// UPDATE "books" AS "book"
// SET "title" = _data."title"
// FROM (VALUES ('updated book 1', 1), ('updated book 2', 2)) AS _data("title", "id")
// WHERE "book"."id" = _data."id"
_, err := db.Model(&books).Column("title", "updated_at").Update()
if err != nil {
	panic(err)
}

books = nil
err = db.Model(&books).Order("id").Select()
if err != nil {
	panic(err)
}

fmt.Println(books)

Output:

[Book<Id=1 Title="updated book 1"> Book<Id=2 Title="updated book 2"> Book<Id=3 Title="book 3">]
Example (CompositeType) 
package main

import (
	"fmt"

	"github.com/go-pg/pg/v10/orm"
)

type InventoryItem struct {
	Name       string
	SupplierID int
	Price      float64
}

type OnHand struct {
	tableName struct{} `pg:"on_hand"`

	Item  InventoryItem `pg:"composite:inventory_item"`
	Count int
}

func main() {
	db := connect()
	defer db.Close()

	err := db.Model((*OnHand)(nil)).DropTable(&orm.DropTableOptions{
		IfExists: true,
		Cascade:  true,
	})
	panicIf(err)

	err = db.Model((*InventoryItem)(nil)).DropComposite(&orm.DropCompositeOptions{
		IfExists: true,
	})
	panicIf(err)

	err = db.Model((*InventoryItem)(nil)).CreateComposite(nil)
	panicIf(err)

	err = db.Model((*OnHand)(nil)).CreateTable(nil)
	panicIf(err)

	_, err = db.Model(&OnHand{
		Item: InventoryItem{
			Name:       "fuzzy dice",
			SupplierID: 42,
			Price:      1.99,
		},
		Count: 1000,
	}).Insert()
	panicIf(err)

	onHand := new(OnHand)
	err = db.Model(onHand).Select()
	panicIf(err)

	fmt.Println(onHand.Item.Name, onHand.Item.Price, onHand.Count)
}

Output:

fuzzy dice 1.99 1000
Example (Count) 
db := modelDB()

count, err := db.Model(&Book{}).Count()
if err != nil {
	panic(err)
}

fmt.Println(count)

Output:

3
Example (CountEstimate) 
db := modelDB()

count, err := db.Model(&Book{}).CountEstimate(0)
if err != nil {
	panic(err)
}

fmt.Println(count)

Output:

3
Example (CreateTable) 
type Model1 struct {
	Id int
}

type Model2 struct {
	Id   int
	Name string

	Model1Id int     `pg:"on_delete:RESTRICT,on_update: CASCADE"`
	Model1   *Model1 `pg:"rel:has-one"`
}

for _, model := range []interface{}{&Model1{}, &Model2{}} {
	err := pgdb.Model(model).CreateTable(&orm.CreateTableOptions{
		Temp:          true, // create temp table
		FKConstraints: true,
	})
	panicIf(err)
}

var info []struct {
	ColumnName string
	DataType   string
}
_, err := pgdb.Query(&info, `
		SELECT column_name, data_type
		FROM information_schema.columns
		WHERE table_name = 'model2'
	`)
panicIf(err)
fmt.Println(info)

Output:

[{id bigint} {name text} {model1_id bigint}]
Example (CustomType) 
package main

import (
	"fmt"
	"time"

	"github.com/go-pg/pg/v10/orm"
	"github.com/go-pg/pg/v10/types"
)

const pgTimeFormat = "15:04:05.999999999"

type Time struct {
	time.Time
}

var _ types.ValueAppender = (*Time)(nil)

func (tm Time) AppendValue(b []byte, flags int) ([]byte, error) {
	if flags == 1 {
		b = append(b, '\'')
	}
	b = tm.UTC().AppendFormat(b, pgTimeFormat)
	if flags == 1 {
		b = append(b, '\'')
	}
	return b, nil
}

var _ types.ValueScanner = (*Time)(nil)

func (tm *Time) ScanValue(rd types.Reader, n int) error {
	if n <= 0 {
		tm.Time = time.Time{}
		return nil
	}

	tmp, err := rd.ReadFullTemp()
	if err != nil {
		return err
	}

	tm.Time, err = time.ParseInLocation(pgTimeFormat, string(tmp), time.UTC)
	if err != nil {
		return err
	}

	return nil
}

type Event struct {
	Id   int
	Time Time `pg:"type:time"`
}

func main() {
	db := connect()
	defer db.Close()

	err := db.Model((*Event)(nil)).CreateTable(&orm.CreateTableOptions{
		Temp: true,
	})
	panicIf(err)

	_, err = db.Model(&Event{
		Time: Time{time.Date(0, 0, 0, 12, 00, 00, 00, time.UTC)}, // noon
	}).Insert()
	panicIf(err)

	evt := new(Event)
	err = db.Model(evt).Select()
	panicIf(err)

	fmt.Println(evt.Time)
}

Output:

0000-01-01 12:00:00 +0000 UTC
Example (Delete) 
db := modelDB()

book := &Book{
	Title:    "title 1",
	AuthorID: 1,
}
_, err := db.Model(book).Insert()
if err != nil {
	panic(err)
}

_, err = db.Model(book).WherePK().Delete()
if err != nil {
	panic(err)
}

err = db.Model(book).WherePK().Select()
fmt.Println(err)

Output:

pg: no rows in result set
Example (DeleteMultipleRows) 
db := modelDB()

ids := pg.In([]int{1, 2, 3})
res, err := db.Model((*Book)(nil)).Where("id IN (?)", ids).Delete()
if err != nil {
	panic(err)
}
fmt.Println("deleted", res.RowsAffected())

count, err := db.Model((*Book)(nil)).Count()
if err != nil {
	panic(err)
}
fmt.Println("left", count)

Output:

deleted 3
left 0
Example (DiscardUnknownColumns) 
type Model1 struct {
}

var model1 Model1
_, err := pgdb.QueryOne(&model1, "SELECT 1 AS id")
fmt.Printf("Model1: %v\n", err)

type Model2 struct {
	tableName struct{} `pg:",discard_unknown_columns"`
}

var model2 Model2
_, err = pgdb.QueryOne(&model2, "SELECT 1 AS id")
fmt.Printf("Model2: %v\n", err)

Output:

Model1: pg: can't find column=id in model=Model1 (prefix the column with underscore or use discard_unknown_columns)
Model2: <nil>
Example (Exists) 
db := modelDB()

var books []Book
exists, err := db.Model(&books).Where("author_id = ?", 1).Exists()
if err != nil {
	panic(err)
}

fmt.Println(exists)

Output:

true
Example (ForEach) 
err := pgdb.Model((*Book)(nil)).
	OrderExpr("id ASC").
	ForEach(func(b *Book) error {
		fmt.Println(b)
		return nil
	})
if err != nil {
	panic(err)
}

Output:

Book<Id=1 Title="book 1">
Book<Id=2 Title="book 2">
Book<Id=3 Title="book 3">
Example (HasMany) 
type Profile struct {
	Id     int
	Lang   string
	Active bool
	UserId int
}

// User has many profiles.
type User struct {
	Id       int
	Name     string
	Profiles []*Profile `pg:"rel:has-many"`
}

db := connect()
defer db.Close()

qs := []string{
	"CREATE TEMP TABLE users (id int, name text)",
	"CREATE TEMP TABLE profiles (id int, lang text, active bool, user_id int)",
	"INSERT INTO users VALUES (1, 'user 1')",
	"INSERT INTO profiles VALUES (1, 'en', TRUE, 1), (2, 'ru', TRUE, 1), (3, 'md', FALSE, 1)",
}
for _, q := range qs {
	_, err := db.Exec(q)
	if err != nil {
		panic(err)
	}
}

// Select user and all his active profiles with following queries:
//
// SELECT "user".* FROM "users" AS "user" ORDER BY "user"."id" LIMIT 1
//
// SELECT "profile".* FROM "profiles" AS "profile"
// WHERE (active IS TRUE) AND (("profile"."user_id") IN ((1)))

var user User
err := db.Model(&user).
	Column("user.*").
	Relation("Profiles", func(q *pg.Query) (*pg.Query, error) {
		return q.Where("active IS TRUE"), nil
	}).
	First()
if err != nil {
	panic(err)
}
fmt.Println(user.Id, user.Name, user.Profiles[0], user.Profiles[1])

Output:

1 user 1 &{1 en true 1} &{2 ru true 1}
Example (HasManySelf) 
type Item struct {
	Id       int
	Items    []Item `pg:"rel:has-many,join_fk:parent_id"`
	ParentId int
}

db := connect()
defer db.Close()

qs := []string{
	"CREATE TEMP TABLE items (id int, parent_id int)",
	"INSERT INTO items VALUES (1, NULL), (2, 1), (3, 1)",
}
for _, q := range qs {
	_, err := db.Exec(q)
	if err != nil {
		panic(err)
	}
}

// Select item and all subitems with following queries:
//
// SELECT "item".* FROM "items" AS "item" ORDER BY "item"."id" LIMIT 1
//
// SELECT "item".* FROM "items" AS "item" WHERE (("item"."parent_id") IN ((1)))

var item Item
err := db.Model(&item).Column("item.*").Relation("Items").First()
if err != nil {
	panic(err)
}
fmt.Println("Item", item.Id)
fmt.Println("Subitems", item.Items[0].Id, item.Items[1].Id)

Output:

Item 1
Subitems 2 3
Example (HasOne) 
type Profile struct {
	Id   int
	Lang string
}

// User has one profile.
type User struct {
	Id        int
	Name      string
	ProfileId int
	Profile   *Profile `pg:"rel:has-one"`
}

db := connect()
defer db.Close()

qs := []string{
	"CREATE TEMP TABLE users (id int, name text, profile_id int)",
	"CREATE TEMP TABLE profiles (id int, lang text)",
	"INSERT INTO users VALUES (1, 'user 1', 1), (2, 'user 2', 2)",
	"INSERT INTO profiles VALUES (1, 'en'), (2, 'ru')",
}
for _, q := range qs {
	_, err := db.Exec(q)
	if err != nil {
		panic(err)
	}
}

// Select users joining their profiles with following query:
//
// SELECT
//   "user".*,
//   "profile"."id" AS "profile__id",
//   "profile"."lang" AS "profile__lang"
// FROM "users" AS "user"
// LEFT JOIN "profiles" AS "profile" ON "profile"."id" = "user"."profile_id"

var users []User
err := db.Model(&users).
	Column("user.*").
	Relation("Profile").
	Select()
if err != nil {
	panic(err)
}

fmt.Println(len(users), "results")
fmt.Println(users[0].Id, users[0].Name, users[0].Profile)
fmt.Println(users[1].Id, users[1].Name, users[1].Profile)

Output:

2 results
1 user 1 &{1 en}
2 user 2 &{2 ru}
Example (HstoreStructTag) 
type Item struct {
	Id    int64
	Attrs map[string]string `pg:",hstore"` // marshalled as PostgreSQL hstore
}

_, err := pgdb.Exec(`CREATE TEMP TABLE items (id serial, attrs hstore)`)
if err != nil {
	panic(err)
}
defer pgdb.Exec("DROP TABLE items")

item1 := Item{
	Id:    1,
	Attrs: map[string]string{"hello": "world"},
}
_, err = pgdb.Model(&item1).Insert()
if err != nil {
	panic(err)
}

var item Item
err = pgdb.Model(&item).Where("id = ?", 1).Select()
if err != nil {
	panic(err)
}
fmt.Println(item)

Output:

{1 map[hello:world]}
Example (Insert) 
db := modelDB()

book := &Book{
	Title:    "new book",
	AuthorID: 1,
}

_, err := db.Model(book).Insert()
if err != nil {
	panic(err)
}
fmt.Println(book)

Output:

Book<Id=4 Title="new book">
Example (InsertDynamicTableName) 
type NamelessModel struct {
	tableName struct{} `pg:"_"` // "_" means no name
	Id        int
}

db := modelDB()

err := db.Model((*NamelessModel)(nil)).Table("dynamic_name").CreateTable(nil)
panicIf(err)

row123 := &NamelessModel{
	Id: 123,
}
_, err = db.Model(row123).Table("dynamic_name").Insert()
panicIf(err)

row := new(NamelessModel)
err = db.Model(row).Table("dynamic_name").First()
panicIf(err)
fmt.Println("id is", row.Id)

err = db.Model((*NamelessModel)(nil)).Table("dynamic_name").DropTable(nil)
panicIf(err)

Output:

id is 123
Example (InsertOnConflictDoNothing) 
db := modelDB()

book := &Book{
	ID:    100,
	Title: "book 100",
}

for i := 0; i < 2; i++ {
	res, err := db.Model(book).OnConflict("DO NOTHING").Insert()
	if err != nil {
		panic(err)
	}
	if res.RowsAffected() > 0 {
		fmt.Println("created")
	} else {
		fmt.Println("did nothing")
	}
}

_, err := db.Model(book).WherePK().Delete()
if err != nil {
	panic(err)
}

Output:

created
did nothing
Example (InsertOnConflictDoUpdate) 
db := modelDB()

var book *Book
for i := 0; i < 2; i++ {
	book = &Book{
		ID:    100,
		Title: fmt.Sprintf("title version #%d", i),
	}
	_, err := db.Model(book).
		OnConflict("(id) DO UPDATE").
		Set("title = EXCLUDED.title").
		Insert()
	if err != nil {
		panic(err)
	}

	err = db.Model(book).WherePK().Select()
	if err != nil {
		panic(err)
	}
	fmt.Println(book)
}

_, err := db.Model(book).WherePK().Delete()
if err != nil {
	panic(err)
}

Output:

Book<Id=100 Title="title version #0">
Book<Id=100 Title="title version #1">
Example (ManyToMany) 
package main

import (
	"fmt"

	"github.com/go-pg/pg/v10"
	"github.com/go-pg/pg/v10/orm"
)

func init() {
	// Register many to many model so ORM can better recognize m2m relation.
	// This should be done before dependant models are used.
	orm.RegisterTable((*OrderToItem)(nil))
}

type Order struct {
	Id    int
	Items []Item `pg:"many2many:order_to_items"`
}

type Item struct {
	Id int
}

type OrderToItem struct {
	OrderId int
	ItemId  int
}

func main() {
	db := connect()
	defer db.Close()

	if err := createManyToManyTables(db); err != nil {
		panic(err)
	}

	values := []interface{}{
		&Item{Id: 1},
		&Item{Id: 2},
		&Order{Id: 1},
		&OrderToItem{OrderId: 1, ItemId: 1},
		&OrderToItem{OrderId: 1, ItemId: 2},
	}
	for _, v := range values {
		_, err := db.Model(v).Insert()
		if err != nil {
			panic(err)
		}
	}

	// Select order and all items with following queries:
	//
	// SELECT "order"."id" FROM "orders" AS "order" ORDER BY "order"."id" LIMIT 1
	//
	// SELECT order_to_items.*, "item"."id" FROM "items" AS "item"
	// JOIN order_to_items AS order_to_items ON (order_to_items."order_id") IN (1)
	// WHERE ("item"."id" = order_to_items."item_id")

	order := new(Order)
	err := db.Model(order).Relation("Items").First()
	if err != nil {
		panic(err)
	}
	fmt.Println("Order", order.Id, "Items", order.Items[0].Id, order.Items[1].Id)

	// Select order and all items sorted by id with following queries:
	//
	// SELECT "order"."id" FROM "orders" AS "order" ORDER BY "order"."id" LIMIT 1
	//
	// SELECT order_to_items.*, "item"."id" FROM "items" AS "item"
	// JOIN order_to_items AS order_to_items ON (order_to_items."order_id") IN (1)
	// WHERE ("item"."id" = order_to_items."item_id")
	// ORDER BY item.id DESC

	order = new(Order)
	err = db.Model(order).
		Relation("Items", func(q *pg.Query) (*pg.Query, error) {
			q = q.OrderExpr("item.id DESC")
			return q, nil
		}).
		First()
	if err != nil {
		panic(err)
	}
	fmt.Println("Order", order.Id, "Items", order.Items[0].Id, order.Items[1].Id)

}

func createManyToManyTables(db *pg.DB) error {
	models := []interface{}{
		(*Order)(nil),
		(*Item)(nil),
		(*OrderToItem)(nil),
	}
	for _, model := range models {
		err := db.Model(model).CreateTable(&orm.CreateTableOptions{
			Temp: true,
		})
		if err != nil {
			return err
		}
	}
	return nil
}

Output:

Order 1 Items 1 2
Order 1 Items 2 1
Example (ManyToManySelf) 
package main

import (
	"fmt"

	"github.com/go-pg/pg/v10"
	"github.com/go-pg/pg/v10/orm"
)

func init() {
	// Register many to many model so ORM can better recognize m2m relation.
	// This should be done before dependant models are used.
	orm.RegisterTable((*ElemToElem)(nil))
}

type Elem struct {
	Id    int
	Elems []Elem `pg:"many2many:elem_to_elems,join_fk:sub_id"`
}

type ElemToElem struct {
	ElemId int
	SubId  int
}

func createManyToManySefTables(db *pg.DB) error {
	models := []interface{}{
		(*Elem)(nil),
		(*ElemToElem)(nil),
	}
	for _, model := range models {
		err := db.Model(model).CreateTable(&orm.CreateTableOptions{
			Temp: true,
		})
		if err != nil {
			return err
		}
	}
	return nil
}

func main() {
	db := connect()
	defer db.Close()

	if err := createManyToManySefTables(db); err != nil {
		panic(err)
	}

	values := []interface{}{
		&Elem{Id: 1},
		&Elem{Id: 2},
		&Elem{Id: 3},
		&ElemToElem{ElemId: 1, SubId: 2},
		&ElemToElem{ElemId: 1, SubId: 3},
	}
	for _, v := range values {
		_, err := db.Model(v).Insert()
		if err != nil {
			panic(err)
		}
	}

	// Select elem and all subelems with following queries:
	//
	// SELECT "elem"."id" FROM "elems" AS "elem" ORDER BY "elem"."id" LIMIT 1
	//
	// SELECT elem_to_elems.*, "elem"."id" FROM "elems" AS "elem"
	// JOIN elem_to_elems AS elem_to_elems ON (elem_to_elems."elem_id") IN (1)
	// WHERE ("elem"."id" = elem_to_elems."sub_id")

	elem := new(Elem)
	err := db.Model(elem).Relation("Elems").First()
	if err != nil {
		panic(err)
	}
	fmt.Println("Elem", elem.Id)
	fmt.Println("Subelems", elem.Elems[0].Id, elem.Elems[1].Id)
}

Output:

Elem 1
Subelems 2 3
Example (NullEmptyValue) 
type Example struct {
	Hello string
}

var str sql.NullString
_, err := pgdb.QueryOne(pg.Scan(&str), "SELECT ?hello", &Example{Hello: ""})
if err != nil {
	panic(err)
}
fmt.Println(str.Valid)

Output:

false
Example (PostgresArrayStructTag) 
type Item struct {
	Id      int64
	Emails  []string `pg:",array"` // marshalled as PostgreSQL array
	Numbers [][]int  `pg:",array"` // marshalled as PostgreSQL array
}

_, err := pgdb.Exec(`CREATE TEMP TABLE items (id serial, emails text[], numbers int[][])`)
panicIf(err)
defer pgdb.Exec("DROP TABLE items")

item1 := &Item{
	Id:      1,
	Emails:  []string{"one@example.com", "two@example.com"},
	Numbers: [][]int{{1, 2}, {3, 4}},
}
_, err = pgdb.Model(item1).Insert()
panicIf(err)

item := new(Item)
err = pgdb.Model(item).Where("id = ?", 1).Select()
panicIf(err)
fmt.Println(item)

Output:

&{1 [one@example.com two@example.com] [[1 2] [3 4]]}
Example (Select) 
db := modelDB()

book := &Book{
	ID: 1,
}
err := db.Model(book).WherePK().Select()
if err != nil {
	panic(err)
}
fmt.Println(book)

Output:

Book<Id=1 Title="book 1">
Example (SelectAllColumns) 
db := modelDB()

var book Book
err := db.Model(&book).Column("book.*").First()
if err != nil {
	panic(err)
}
fmt.Println(book, book.AuthorID)

Output:

Book<Id=1 Title="book 1"> 1
Example (SelectAndCount) 
db := modelDB()

var books []Book
count, err := db.Model(&books).OrderExpr("id ASC").Limit(2).SelectAndCount()
if err != nil {
	panic(err)
}

fmt.Println(count)
fmt.Println(books)

Output:

3
[Book<Id=1 Title="book 1"> Book<Id=2 Title="book 2">]
Example (SelectApplyFunc) 
db := modelDB()

var authorId int
var editorId int

filter := func(q *pg.Query) (*pg.Query, error) {
	if authorId != 0 {
		q = q.Where("author_id = ?", authorId)
	}
	if editorId != 0 {
		q = q.Where("editor_id = ?", editorId)
	}
	return q, nil
}

var books []Book
authorId = 1
err := db.Model(&books).
	Apply(filter).
	Select()
if err != nil {
	panic(err)
}
fmt.Println(books)

Output:

[Book<Id=1 Title="book 1"> Book<Id=2 Title="book 2">]
Example (SelectFirstRow) 
db := modelDB()

var firstBook Book
err := db.Model(&firstBook).First()
if err != nil {
	panic(err)
}
fmt.Println(firstBook)

Output:

Book<Id=1 Title="book 1">
Example (SelectGroupBy) 
db := modelDB()

var res []struct {
	AuthorId  int
	BookCount int
}

err := db.Model(&Book{}).
	Column("author_id").
	ColumnExpr("count(*) AS book_count").
	Group("author_id").
	OrderExpr("book_count DESC").
	Select(&res)
if err != nil {
	panic(err)
}
fmt.Println("len", len(res))
fmt.Printf("author %d has %d books\n", res[0].AuthorId, res[0].BookCount)
fmt.Printf("author %d has %d books\n", res[1].AuthorId, res[1].BookCount)

Output:

len 2
author 1 has 2 books
author 11 has 1 books
Example (SelectLastRow) 
db := modelDB()

var lastBook Book
err := db.Model(&lastBook).Last()
if err != nil {
	panic(err)
}
fmt.Println(lastBook)

Output:

Book<Id=3 Title="book 3">
Example (SelectOrInsert) 
db := modelDB()

author := Author{
	Name: "R. Scott Bakker",
}
created, err := db.Model(&author).
	Column("id").
	Where("name = ?name").
	OnConflict("DO NOTHING"). // OnConflict is optional
	Returning("id").
	SelectOrInsert()
if err != nil {
	panic(err)
}
fmt.Println(created, author)

Output:

true Author<ID=2 Name="R. Scott Bakker">
Example (SelectSQLExpression) 
db := modelDB()

var ids []int
err := db.Model(&Book{}).
	ColumnExpr("array_agg(book.id)").
	Select(pg.Array(&ids))
if err != nil {
	panic(err)
}
fmt.Println(ids)

Output:

[1 2 3]
Example (SelectSomeColumns) 
db := modelDB()

var book Book
err := db.Model(&book).
	Column("book.id", "book.title").
	OrderExpr("book.id ASC").
	Limit(1).
	Select()
if err != nil {
	panic(err)
}

fmt.Println(book)

Output:

Book<Id=1 Title="book 1">
Example (SelectSomeColumnsIntoVars) 
db := modelDB()

var id int
var title string
err := db.Model(&Book{}).
	Column("book.id", "book.title").
	OrderExpr("book.id ASC").
	Limit(1).
	Select(&id, &title)
if err != nil {
	panic(err)
}

fmt.Println(id, title)

Output:

1 book 1
Example (SelectWhereGroup) 
db := modelDB()

var books []Book
err := db.Model(&books).
	WhereGroup(func(q *pg.Query) (*pg.Query, error) {
		q = q.WhereOr("id = 1").
			WhereOr("id = 2")
		return q, nil
	}).
	Where("title IS NOT NULL").
	Select()
if err != nil {
	panic(err)
}
fmt.Println(books)

Output:

[Book<Id=1 Title="book 1"> Book<Id=2 Title="book 2">]
Example (SelectWhereIn) 
db := modelDB()

var books []Book
err := db.Model(&books).WhereIn("id IN (?)", []int{1, 2}).Select()
if err != nil {
	panic(err)
}
fmt.Println(books)

Output:

[Book<Id=1 Title="book 1"> Book<Id=2 Title="book 2">]
Example (SelectWith) 
authorBooks := pgdb.Model(&Book{}).Where("author_id = ?", 1)

var books []Book
err := pgdb.Model().
	With("author_books", authorBooks).
	Table("author_books").
	Select(&books)
if err != nil {
	panic(err)
}
fmt.Println(books)

Output:

[Book<Id=1 Title="book 1"> Book<Id=2 Title="book 2">]
Example (SelectWrapWith) 
// WITH author_books AS (
//     SELECT * books WHERE author_id = 1
// )
// SELECT * FROM author_books
var books []Book
err := pgdb.Model(&books).
	Where("author_id = ?", 1).
	WrapWith("author_books").
	Table("author_books").
	Select(&books)
if err != nil {
	panic(err)
}
fmt.Println(books)

Output:

[Book<Id=1 Title="book 1"> Book<Id=2 Title="book 2">]
Example (SoftDelete) 
type Flight struct {
	Id        int
	Name      string
	DeletedAt time.Time `pg:",soft_delete"`
}

err := pgdb.Model((*Flight)(nil)).CreateTable(&orm.CreateTableOptions{
	Temp: true,
})
panicIf(err)

flight1 := &Flight{
	Id: 1,
}
_, err = pgdb.Model(flight1).Insert()
panicIf(err)

// Soft delete.
_, err = pgdb.Model(flight1).WherePK().Delete()
panicIf(err)

// Count visible flights.
count, err := pgdb.Model((*Flight)(nil)).Count()
panicIf(err)
fmt.Println("count", count)

// Count soft deleted flights.
deletedCount, err := pgdb.Model((*Flight)(nil)).Deleted().Count()
panicIf(err)
fmt.Println("deleted count", deletedCount)

// Actually delete the flight.
_, err = pgdb.Model(flight1).WherePK().ForceDelete()
panicIf(err)

// Count soft deleted flights.
deletedCount, err = pgdb.Model((*Flight)(nil)).Deleted().Count()
panicIf(err)
fmt.Println("deleted count", deletedCount)

Output:

count 0
deleted count 1
deleted count 0
Example (SoftDeleteCustom) 
package main

import (
	"fmt"
	"time"

	"github.com/go-pg/pg/v10/types"
)

type CustomTime struct {
	Time time.Time
}

var _ types.ValueScanner = (*CustomTime)(nil)

func (tm *CustomTime) ScanValue(rd types.Reader, n int) error {
	var err error
	tm.Time, err = types.ScanTime(rd, n)
	return err
}

var _ types.ValueAppender = (*CustomTime)(nil)

func (tm *CustomTime) AppendValue(b []byte, flags int) ([]byte, error) {
	return types.AppendTime(b, tm.Time, flags), nil
}

type Video struct {
	Id        int
	Name      string
	DeletedAt CustomTime `pg:",soft_delete"`
}

func main() {
	video1 := &Video{
		Id: 1,
	}
	_, err := pgdb.Model(video1).Insert()
	panicIf(err)

	// Soft delete.
	_, err = pgdb.Model(video1).WherePK().Delete()
	panicIf(err)

	// Count visible videos.
	count, err := pgdb.Model((*Video)(nil)).Count()
	panicIf(err)
	fmt.Println("count", count)

	// Count soft deleted videos.
	deletedCount, err := pgdb.Model((*Video)(nil)).Deleted().Count()
	panicIf(err)
	fmt.Println("deleted count", deletedCount)

	// Actually delete the video.
	_, err = pgdb.Model(video1).WherePK().ForceDelete()
	panicIf(err)

	// Count soft deleted videos.
	deletedCount, err = pgdb.Model((*Video)(nil)).Deleted().Count()
	panicIf(err)
	fmt.Println("deleted count", deletedCount)

}

Output:

count 0
deleted count 1
deleted count 0
Example (Update) 
db := modelDB()

book := &Book{ID: 1}
err := db.Model(book).WherePK().Select()
if err != nil {
	panic(err)
}

book.Title = "updated book 1"
_, err = db.Model(book).WherePK().Update()
if err != nil {
	panic(err)
}

err = db.Model(book).WherePK().Select()
if err != nil {
	panic(err)
}

fmt.Println(book)

Output:

Book<Id=1 Title="updated book 1">
Example (UpdateNotZero) 
db := modelDB()

book := &Book{
	ID:    1,
	Title: "updated book 1",
}
_, err := db.Model(book).WherePK().UpdateNotZero()
if err != nil {
	panic(err)
}

book = new(Book)
err = db.Model(book).Where("id = ?", 1).Select()
if err != nil {
	panic(err)
}

fmt.Println(book)

Output:

Book<Id=1 Title="updated book 1">
Example (UpdateSetValues) 
db := modelDB()

var book Book
_, err := db.Model(&book).
	Set("title = concat(?, title, ?)", "prefix ", " suffix").
	Where("id = ?", 1).
	Returning("*").
	Update()
if err != nil {
	panic(err)
}

fmt.Println(book)

Output:

Book<Id=1 Title="prefix book 1 suffix">
Example (UpdateSomeColumns) 
db := modelDB()

book := Book{
	ID:       1,
	Title:    "updated book 1", // only this column is going to be updated
	AuthorID: 2,
}
_, err := db.Model(&book).Column("title").WherePK().Returning("*").Update()
if err != nil {
	panic(err)
}

fmt.Println(book, book.AuthorID)

Output:

Book<Id=1 Title="updated book 1"> 1
Example (UpdateSomeColumns2) 
db := modelDB()

book := Book{
	ID:       1,
	Title:    "updated book 1",
	AuthorID: 2, // this column will not be updated
}
_, err := db.Model(&book).Set("title = ?title").WherePK().Returning("*").Update()
if err != nil {
	panic(err)
}

fmt.Println(book, book.AuthorID)

Output:

Book<Id=1 Title="updated book 1"> 1
Example (UpdateUseZeroBool) 
type Event struct {
	ID     int
	Active bool `pg:",use_zero"`
}

db := pg.Connect(pgOptions())
defer db.Close()

err := db.Model((*Event)(nil)).CreateTable(&orm.CreateTableOptions{
	Temp: true,
})
if err != nil {
	panic(err)
}

event := &Event{
	ID:     1,
	Active: true,
}
_, err = db.Model(event).Insert()
if err != nil {
	panic(err)
}

fmt.Println(event)

event.Active = false
_, err = db.Model(event).WherePK().UpdateNotZero()
if err != nil {
	panic(err)
}

event2 := new(Event)
err = db.Model(event2).Where("id = ?", 1).Select()
if err != nil {
	panic(err)
}

fmt.Println(event2)

Output:

&{1 true}
&{1 false}

func (DB) ModelContext 

func (db DB) ModelContext(c context.Context, model ...interface{}) *Query

func (*DB) Options 

func (db *DB) Options() *Options

Options returns read-only Options that were used to connect to the DB.

func (DB) Param 

func (db DB) Param(param string) interface{}

Param returns value for the param.

func (DB) Ping 

func (db DB) Ping(ctx context.Context) error

Ping verifies a connection to the database is still alive, establishing a connection if necessary.

func (DB) PoolStats 

func (db DB) PoolStats() *PoolStats

PoolStats returns connection pool stats.

func (DB) Prepare 

func (db DB) Prepare(q string) (*Stmt, error)

Prepare creates a prepared statement for later queries or executions. Multiple queries or executions may be run concurrently from the returned statement.

Example 
stmt, err := pgdb.Prepare(`SELECT $1::text, $2::text`)
panicIf(err)

var s1, s2 string
_, err = stmt.QueryOne(pg.Scan(&s1, &s2), "foo", "bar")
panicIf(err)
fmt.Println(s1, s2)

Output:

foo bar

func (DB) Query 

func (db DB) Query(model, query interface{}, params ...interface{}) (res Result, err error)

Query executes a query that returns rows, typically a SELECT. The params are for any placeholders in the query.

Example 
package main

import (
	"fmt"

	"github.com/go-pg/pg/v10"
)

func CreateUser(db *pg.DB, user *User) error {
	_, err := db.QueryOne(user, `
		INSERT INTO users (name, emails) VALUES (?name, ?emails)
		RETURNING id
	`, user)
	return err
}

func GetUser(db *pg.DB, id int64) (*User, error) {
	var user User
	_, err := db.QueryOne(&user, `SELECT * FROM users WHERE id = ?`, id)
	return &user, err
}

func GetUsers(db *pg.DB) ([]User, error) {
	var users []User
	_, err := db.Query(&users, `SELECT * FROM users`)
	return users, err
}

func GetUsersByIds(db *pg.DB, ids []int64) ([]User, error) {
	var users []User
	_, err := db.Query(&users, `SELECT * FROM users WHERE id IN (?)`, pg.In(ids))
	return users, err
}

func CreateStory(db *pg.DB, story *Story) error {
	_, err := db.QueryOne(story, `
		INSERT INTO stories (title, author_id) VALUES (?title, ?author_id)
		RETURNING id
	`, story)
	return err
}

// GetStory returns story with associated author.
func GetStory(db *pg.DB, id int64) (*Story, error) {
	var story Story
	_, err := db.QueryOne(&story, `
		SELECT s.*,
			u.id AS author__id, u.name AS author__name, u.emails AS author__emails
		FROM stories AS s, users AS u
		WHERE s.id = ? AND u.id = s.author_id
	`, id)
	return &story, err
}

func main() {
	db := pg.Connect(&pg.Options{
		User:     "postgres",
		Password: "postgres",
	})

	err := createSchema(db)
	panicIf(err)

	user1 := &User{
		Name:   "admin",
		Emails: []string{"admin1@admin", "admin2@admin"},
	}
	err = CreateUser(db, user1)
	panicIf(err)

	err = CreateUser(db, &User{
		Name:   "root",
		Emails: []string{"root1@root", "root2@root"},
	})
	panicIf(err)

	story1 := &Story{
		Title:    "Cool story",
		AuthorId: user1.Id,
	}
	err = CreateStory(db, story1)
	panicIf(err)

	user, err := GetUser(db, user1.Id)
	panicIf(err)

	users, err := GetUsers(db)
	panicIf(err)

	story, err := GetStory(db, story1.Id)
	panicIf(err)

	fmt.Println(user)
	fmt.Println(users)
	fmt.Println(story)
}

Output:

User<1 admin [admin1@admin admin2@admin]>
[User<1 admin [admin1@admin admin2@admin]> User<2 root [root1@root root2@root]>]
Story<1 Cool story User<1 admin [admin1@admin admin2@admin]>>

func (DB) QueryContext 

func (db DB) QueryContext(c context.Context, model, query interface{}, params ...interface{}) (Result, error)

func (DB) QueryOne 

func (db DB) QueryOne(model, query interface{}, params ...interface{}) (Result, error)

QueryOne acts like Query, but query must return only one row. It returns ErrNoRows error when query returns zero rows or ErrMultiRows when query returns multiple rows.

Example 
var user struct {
	Name string
}

res, err := pgdb.QueryOne(&user, `
        WITH users (name) AS (VALUES (?))
        SELECT * FROM users
    `, "admin")
panicIf(err)
fmt.Println(res.RowsAffected())
fmt.Println(user)

Output:

1
{admin}
Example (Returning_id) 
_, err := pgdb.Exec(`CREATE TEMP TABLE users(id serial, name varchar(500))`)
panicIf(err)

var user struct {
	Id   int32
	Name string
}
user.Name = "admin"

_, err = pgdb.QueryOne(&user, `
        INSERT INTO users (name) VALUES (?name) RETURNING id
    `, &user)
panicIf(err)
fmt.Println(user)

Output:

{1 admin}

func (DB) QueryOneContext 

func (db DB) QueryOneContext(
	ctx context.Context, model, query interface{}, params ...interface{},
) (Result, error)

func (DB) RunInTransaction 

func (db DB) RunInTransaction(ctx context.Context, fn func(*Tx) error) error

RunInTransaction runs a function in a transaction. If function returns an error transaction is rolled back, otherwise transaction is committed.

Example 
db := txExample()

incrInTx := func(db *pg.DB) error {
	// Transaction is automatically rolled back on error.
	return db.RunInTransaction(ctx, func(tx *pg.Tx) error {
		var counter int
		_, err := tx.QueryOne(
			pg.Scan(&counter), `SELECT counter FROM tx_test FOR UPDATE`)
		if err != nil {
			return err
		}

		counter++

		_, err = tx.Exec(`UPDATE tx_test SET counter = ?`, counter)
		return err
	})
}

var wg sync.WaitGroup
for i := 0; i < 10; i++ {
	wg.Add(1)
	go func() {
		defer wg.Done()
		err := incrInTx(db)
		panicIf(err)
	}()
}
wg.Wait()

var counter int
_, err := db.QueryOne(pg.Scan(&counter), `SELECT counter FROM tx_test`)
panicIf(err)
fmt.Println(counter)

Output:

10

func (*DB) String 

func (db *DB) String() string

func (*DB) WithContext 

func (db *DB) WithContext(ctx context.Context) *DB

WithContext returns a copy of the DB that uses the ctx.

func (*DB) WithParam 

func (db *DB) WithParam(param string, value interface{}) *DB

WithParam returns a copy of the DB that replaces the param with the value in queries.

func (*DB) WithTimeout 

func (db *DB) WithTimeout(d time.Duration) *DB

WithTimeout returns a copy of the DB that uses d as the read/write timeout.

Example 
var count int
// Use bigger timeout since this query is known to be slow.
_, err := pgdb.WithTimeout(time.Minute).QueryOne(pg.Scan(&count), `
		SELECT count(*) FROM big_table
	`)
panicIf(err)

type DBI added in v10.9.0 

type DBI interface {
	Model(model ...interface{}) *Query
	ModelContext(c context.Context, model ...interface{}) *Query

	Exec(query interface{}, params ...interface{}) (Result, error)
	ExecContext(c context.Context, query interface{}, params ...interface{}) (Result, error)
	ExecOne(query interface{}, params ...interface{}) (Result, error)
	ExecOneContext(c context.Context, query interface{}, params ...interface{}) (Result, error)
	Query(model, query interface{}, params ...interface{}) (Result, error)
	QueryContext(c context.Context, model, query interface{}, params ...interface{}) (Result, error)
	QueryOne(model, query interface{}, params ...interface{}) (Result, error)
	QueryOneContext(c context.Context, model, query interface{}, params ...interface{}) (Result, error)

	Begin() (*Tx, error)
	RunInTransaction(ctx context.Context, fn func(*Tx) error) error

	CopyFrom(r io.Reader, query interface{}, params ...interface{}) (Result, error)
	CopyTo(w io.Writer, query interface{}, params ...interface{}) (Result, error)
}

DBI is a DB interface implemented by *DB and *Tx.

type Error 

type Error interface {
	error

	// Field returns a string value associated with an error field.
	//
	// https://www.postgresql.org/docs/10/static/protocol-error-fields.html
	Field(field byte) string

	// IntegrityViolation reports whether an error is a part of
	// Integrity Constraint Violation class of errors.
	//
	// https://www.postgresql.org/docs/10/static/errcodes-appendix.html
	IntegrityViolation() bool
}

Error represents an error returned by PostgreSQL server using PostgreSQL ErrorResponse protocol.

https://www.postgresql.org/docs/10/static/protocol-message-formats.html

Example 
video := &Video{
	Id: 123,
}
_, err := pgdb.Model(video).Insert()
panicIf(err)

_, err = pgdb.Model(video).Insert()
if err != nil {
	pgErr, ok := err.(pg.Error)
	if ok && pgErr.IntegrityViolation() {
		fmt.Println("video already exists:", err)
	} else if pgErr.Field('S') == "PANIC" {
		panic(err)
	}
}

Output:

video already exists: ERROR #23505 duplicate key value violates unique constraint "videos_pkey"

type Ident 

type Ident = types.Ident

Ident represents a SQL identifier, e.g. table or column name.

Example 
db := modelDB()

var book Book
err := db.Model(&book).Where("? = 1", pg.Ident("id")).Select()
if err != nil {
	panic(err)
}
fmt.Println(book)

Output:

Book<Id=1 Title="book 1">

type IntSet 

type IntSet map[int64]struct{}

IntSet is a set of int64 values.

func (IntSet) AddColumnScanner 

func (IntSet) AddColumnScanner(_ orm.ColumnScanner) error

AddColumnScanner ...

func (*IntSet) Init 

func (set *IntSet) Init() error

Init initializes the IntSet.

func (*IntSet) NextColumnScanner 

func (set *IntSet) NextColumnScanner() orm.ColumnScanner

NextColumnScanner ...

func (*IntSet) ScanColumn 

func (set *IntSet) ScanColumn(col types.ColumnInfo, rd types.Reader, n int) error

ScanColumn scans the columns and appends them to `IntSet`.

type Ints 

type Ints []int64

Ints is a type alias for a slice of int64 values.

Example 
var nums pg.Ints
_, err := pgdb.Query(&nums, `SELECT generate_series(0, 10)`)
panicIf(err)
fmt.Println(nums)

Output:

[0 1 2 3 4 5 6 7 8 9 10]

func (Ints) AddColumnScanner 

func (Ints) AddColumnScanner(_ orm.ColumnScanner) error

AddColumnScanner ...

func (Ints) AppendValue 

func (ints Ints) AppendValue(dst []byte, quote int) ([]byte, error)

AppendValue appends the values from `ints` to the given byte slice.

func (*Ints) Init 

func (ints *Ints) Init() error

Init initializes the Int slice.

func (*Ints) NextColumnScanner 

func (ints *Ints) NextColumnScanner() orm.ColumnScanner

NewColumnScanner ...

func (*Ints) ScanColumn 

func (ints *Ints) ScanColumn(col types.ColumnInfo, rd types.Reader, n int) error

ScanColumn scans the columns and appends them to `ints`.

type Listener 

type Listener struct {
	// contains filtered or unexported fields
}

Listener listens for notifications sent with NOTIFY command. It's NOT safe for concurrent use by multiple goroutines except the Channel API.

Example 
ln := pgdb.Listen(ctx, "mychan")
defer ln.Close()

ch := ln.Channel()

go func() {
	time.Sleep(time.Millisecond)
	_, err := pgdb.Exec("NOTIFY mychan, ?", "hello world")
	panicIf(err)
}()

notif := <-ch
fmt.Println(notif)

Output:

{mychan hello world}

func (*Listener) Channel 

func (ln *Listener) Channel() <-chan Notification

Channel returns a channel for concurrently receiving notifications. It periodically sends Ping notification to test connection health.

The channel is closed with Listener. Receive* APIs can not be used after channel is created.

func (*Listener) ChannelSize 

func (ln *Listener) ChannelSize(size int) <-chan Notification

ChannelSize is like Channel, but creates a Go channel with specified buffer size.

func (*Listener) Close 

func (ln *Listener) Close() error

Close closes the listener, releasing any open resources.

func (*Listener) Listen 

func (ln *Listener) Listen(ctx context.Context, channels ...string) error

Listen starts listening for notifications on channels.

func (*Listener) Receive 

func (ln *Listener) Receive(ctx context.Context) (channel string, payload string, err error)

Receive indefinitely waits for a notification. This is low-level API and in most cases Channel should be used instead.

func (*Listener) ReceiveTimeout 

func (ln *Listener) ReceiveTimeout(
	ctx context.Context, timeout time.Duration,
) (channel, payload string, err error)

ReceiveTimeout waits for a notification until timeout is reached. This is low-level API and in most cases Channel should be used instead.

func (*Listener) String 

func (ln *Listener) String() string

func (*Listener) Unlisten 

func (ln *Listener) Unlisten(ctx context.Context, channels ...string) error

Unlisten stops listening for notifications on channels.

type Notification 

type Notification struct {
	Channel string
	Payload string
}

Notification which is received with LISTEN command.

type NullTime 

type NullTime = types.NullTime

NullTime is a time.Time wrapper that marshals zero time as JSON null and PostgreSQL NULL.

type Options 

type Options struct {
	// Network type, either tcp or unix.
	// Default is tcp.
	Network string
	// TCP host:port or Unix socket depending on Network.
	Addr string

	// Dialer creates new network connection and has priority over
	// Network and Addr options.
	Dialer func(ctx context.Context, network, addr string) (net.Conn, error)

	// Hook that is called after new connection is established
	// and user is authenticated.
	OnConnect func(ctx context.Context, cn *Conn) error

	User     string
	Password string
	Database string

	// ApplicationName is the application name. Used in logs on Pg side.
	// Only available from pg-9.0.
	ApplicationName string

	// TLS config for secure connections.
	TLSConfig *tls.Config

	// Dial timeout for establishing new connections.
	// Default is 5 seconds.
	DialTimeout time.Duration

	// Timeout for socket reads. If reached, commands will fail
	// with a timeout instead of blocking.
	ReadTimeout time.Duration
	// Timeout for socket writes. If reached, commands will fail
	// with a timeout instead of blocking.
	WriteTimeout time.Duration

	// Maximum number of retries before giving up.
	// Default is to not retry failed queries.
	MaxRetries int
	// Whether to retry queries cancelled because of statement_timeout.
	RetryStatementTimeout bool
	// Minimum backoff between each retry.
	// Default is 250 milliseconds; -1 disables backoff.
	MinRetryBackoff time.Duration
	// Maximum backoff between each retry.
	// Default is 4 seconds; -1 disables backoff.
	MaxRetryBackoff time.Duration

	// Maximum number of socket connections.
	// Default is 10 connections per every CPU as reported by runtime.NumCPU.
	PoolSize int
	// Minimum number of idle connections which is useful when establishing
	// new connection is slow.
	MinIdleConns int
	// Connection age at which client retires (closes) the connection.
	// It is useful with proxies like PgBouncer and HAProxy.
	// Default is to not close aged connections.
	MaxConnAge time.Duration
	// Time for which client waits for free connection if all
	// connections are busy before returning an error.
	// Default is 30 seconds if ReadTimeOut is not defined, otherwise,
	// ReadTimeout + 1 second.
	PoolTimeout time.Duration
	// Amount of time after which client closes idle connections.
	// Should be less than server's timeout.
	// Default is 5 minutes. -1 disables idle timeout check.
	IdleTimeout time.Duration
	// Frequency of idle checks made by idle connections reaper.
	// Default is 1 minute. -1 disables idle connections reaper,
	// but idle connections are still discarded by the client
	// if IdleTimeout is set.
	IdleCheckFrequency time.Duration
	// Connections read buffers stored in a sync.Pool to reduce allocations.
	// Using this option you can adjust the initial size of the buffer.
	// Default is 1 Mb.
	ReadBufferInitialSize int
	// Connections write buffers stored in a sync.Pool to reduce allocations.
	// Using this option you can adjust the initial size of the buffer.
	// Default is 64 Kb.
	WriteBufferInitialSize int
}

Options contains database connection options.

func ParseURL 

func ParseURL(sURL string) (*Options, error)

ParseURL parses an URL into options that can be used to connect to PostgreSQL.

func (*Options) ToURL added in v10.11.2 

func (opts *Options) ToURL() string

type PoolStats 

type PoolStats pool.Stats

PoolStats contains the stats of a connection pool.

type Query added in v10.9.0 

type Query = orm.Query

func Model 

func Model(model ...interface{}) *Query

Model returns a new query for the optional model.

func ModelContext 

func ModelContext(c context.Context, model ...interface{}) *Query

ModelContext returns a new query for the optional model with a context.

type QueryEvent 

type QueryEvent struct {
	StartTime time.Time
	DB        orm.DB
	Model     interface{}
	Query     interface{}
	Params    []interface{}

	Result Result
	Err    error

	Stash map[interface{}]interface{}
	// contains filtered or unexported fields
}

QueryEvent ...

func (*QueryEvent) FormattedQuery 

func (e *QueryEvent) FormattedQuery() ([]byte, error)

FormattedQuery returns the formatted query of a query event. The query is only valid until the query Result is returned to the user.

func (*QueryEvent) UnformattedQuery 

func (e *QueryEvent) UnformattedQuery() ([]byte, error)

UnformattedQuery returns the unformatted query of a query event. The query is only valid until the query Result is returned to the user.

type QueryHook 

type QueryHook interface {
	BeforeQuery(context.Context, *QueryEvent) (context.Context, error)
	AfterQuery(context.Context, *QueryEvent) error
}

QueryHook ...

type Result 

type Result = orm.Result

Result summarizes an executed SQL command.

type Safe 

type Safe = types.Safe

Safe represents a safe SQL query.

Example 
db := modelDB()

cond := fmt.Sprintf("id = %d", 1)

var book Book
err := db.Model(&book).Where("?", pg.Safe(cond)).Select()
if err != nil {
	panic(err)
}
fmt.Println(book)

Output:

Book<Id=1 Title="book 1">

type Stmt 

type Stmt struct {
	// contains filtered or unexported fields
}

Stmt is a prepared statement. Stmt is safe for concurrent use by multiple goroutines.

func (*Stmt) Close 

func (stmt *Stmt) Close() error

Close closes the statement.

func (*Stmt) Exec 

func (stmt *Stmt) Exec(params ...interface{}) (Result, error)

Exec executes a prepared statement with the given parameters.

func (*Stmt) ExecContext 

func (stmt *Stmt) ExecContext(c context.Context, params ...interface{}) (Result, error)

ExecContext executes a prepared statement with the given parameters.

func (*Stmt) ExecOne 

func (stmt *Stmt) ExecOne(params ...interface{}) (Result, error)

ExecOne acts like Exec, but query must affect only one row. It returns ErrNoRows error when query returns zero rows or ErrMultiRows when query returns multiple rows.

func (*Stmt) ExecOneContext 

func (stmt *Stmt) ExecOneContext(c context.Context, params ...interface{}) (Result, error)

ExecOneContext acts like ExecOne but additionally receives a context.

func (*Stmt) Query 

func (stmt *Stmt) Query(model interface{}, params ...interface{}) (Result, error)

Query executes a prepared query statement with the given parameters.

func (*Stmt) QueryContext 

func (stmt *Stmt) QueryContext(c context.Context, model interface{}, params ...interface{}) (Result, error)

QueryContext acts like Query but additionally receives a context.

func (*Stmt) QueryOne 

func (stmt *Stmt) QueryOne(model interface{}, params ...interface{}) (Result, error)

QueryOne acts like Query, but query must return only one row. It returns ErrNoRows error when query returns zero rows or ErrMultiRows when query returns multiple rows.

func (*Stmt) QueryOneContext 

func (stmt *Stmt) QueryOneContext(c context.Context, model interface{}, params ...interface{}) (Result, error)

QueryOneContext acts like QueryOne but additionally receives a context.

type Strings 

type Strings []string

Strings is a type alias for a slice of strings.

Example 
var strs pg.Strings
_, err := pgdb.Query(&strs, `
		WITH users AS (VALUES ('foo'), ('bar')) SELECT * FROM users
	`)
panicIf(err)
fmt.Println(strs)

Output:

[foo bar]

func (Strings) AddColumnScanner 

func (Strings) AddColumnScanner(_ orm.ColumnScanner) error

AddColumnScanner ...

func (Strings) AppendValue 

func (strings Strings) AppendValue(dst []byte, quote int) ([]byte, error)

AppendValue appends the values from `strings` to the given byte slice.

func (*Strings) Init 

func (strings *Strings) Init() error

Init initializes the Strings slice.

func (*Strings) NextColumnScanner 

func (strings *Strings) NextColumnScanner() orm.ColumnScanner

NextColumnScanner ...

func (*Strings) ScanColumn 

func (strings *Strings) ScanColumn(col types.ColumnInfo, rd types.Reader, n int) error

ScanColumn scans the columns and appends them to `strings`.

type Tx 

type Tx struct {
	// contains filtered or unexported fields
}

Tx is an in-progress database transaction. It is safe for concurrent use by multiple goroutines.

A transaction must end with a call to Commit or Rollback.

After a call to Commit or Rollback, all operations on the transaction fail with ErrTxDone.

The statements prepared for a transaction by calling the transaction's Prepare or Stmt methods are closed by the call to Commit or Rollback.

func (*Tx) Begin 

func (tx *Tx) Begin() (*Tx, error)

Begin returns current transaction. It does not start new transaction.

func (*Tx) Close 

func (tx *Tx) Close() error

func (*Tx) CloseContext 

func (tx *Tx) CloseContext(ctx context.Context) error

Close calls Rollback if the tx has not already been committed or rolled back.

func (*Tx) Commit 

func (tx *Tx) Commit() error

func (*Tx) CommitContext 

func (tx *Tx) CommitContext(ctx context.Context) error

Commit commits the transaction.

func (*Tx) Context 

func (tx *Tx) Context() context.Context

Context returns the context.Context of the transaction.

func (*Tx) CopyFrom 

func (tx *Tx) CopyFrom(r io.Reader, query interface{}, params ...interface{}) (res Result, err error)

CopyFrom is an alias for DB.CopyFrom.

func (*Tx) CopyTo 

func (tx *Tx) CopyTo(w io.Writer, query interface{}, params ...interface{}) (res Result, err error)

CopyTo is an alias for DB.CopyTo.

func (*Tx) Exec 

func (tx *Tx) Exec(query interface{}, params ...interface{}) (Result, error)

Exec is an alias for DB.Exec.

func (*Tx) ExecContext 

func (tx *Tx) ExecContext(c context.Context, query interface{}, params ...interface{}) (Result, error)

ExecContext acts like Exec but additionally receives a context.

func (*Tx) ExecOne 

func (tx *Tx) ExecOne(query interface{}, params ...interface{}) (Result, error)

ExecOne is an alias for DB.ExecOne.

func (*Tx) ExecOneContext 

func (tx *Tx) ExecOneContext(c context.Context, query interface{}, params ...interface{}) (Result, error)

ExecOneContext acts like ExecOne but additionally receives a context.

func (*Tx) Formatter 

func (tx *Tx) Formatter() orm.QueryFormatter

Formatter is an alias for DB.Formatter.

func (*Tx) Model 

func (tx *Tx) Model(model ...interface{}) *Query

Model is an alias for DB.Model.

func (*Tx) ModelContext 

func (tx *Tx) ModelContext(c context.Context, model ...interface{}) *Query

ModelContext acts like Model but additionally receives a context.

func (*Tx) Prepare 

func (tx *Tx) Prepare(q string) (*Stmt, error)

Prepare creates a prepared statement for use within a transaction.

The returned statement operates within the transaction and can no longer be used once the transaction has been committed or rolled back.

To use an existing prepared statement on this transaction, see Tx.Stmt.

func (*Tx) Query 

func (tx *Tx) Query(model interface{}, query interface{}, params ...interface{}) (Result, error)

Query is an alias for DB.Query.

func (*Tx) QueryContext 

func (tx *Tx) QueryContext(
	c context.Context,
	model interface{},
	query interface{},
	params ...interface{},
) (Result, error)

QueryContext acts like Query but additionally receives a context.

func (*Tx) QueryOne 

func (tx *Tx) QueryOne(model interface{}, query interface{}, params ...interface{}) (Result, error)

QueryOne is an alias for DB.QueryOne.

func (*Tx) QueryOneContext 

func (tx *Tx) QueryOneContext(
	c context.Context,
	model interface{},
	query interface{},
	params ...interface{},
) (Result, error)

QueryOneContext acts like QueryOne but additionally receives a context.

func (*Tx) Rollback 

func (tx *Tx) Rollback() error

func (*Tx) RollbackContext 

func (tx *Tx) RollbackContext(ctx context.Context) error

Rollback aborts the transaction.

func (*Tx) RunInTransaction 

func (tx *Tx) RunInTransaction(ctx context.Context, fn func(*Tx) error) error

RunInTransaction runs a function in the transaction. If function returns an error transaction is rolled back, otherwise transaction is committed.

func (*Tx) Stmt 

func (tx *Tx) Stmt(stmt *Stmt) *Stmt

Stmt returns a transaction-specific prepared statement from an existing statement.

Source Files

View all Source files

Directories

Path Synopsis
internal is a private internal package.
 internal is a private internal package.
parser
pool
The API in this package is not stable and may change without any notice.
 The API in this package is not stable and may change without any notice.
The API in this package is not stable and may change without any notice.
 The API in this package is not stable and may change without any notice.

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