sqlx

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 Go to latest Published: Dec 4, 2016 License: MIT Imports: 12 Imported by: 0

README

sqlx

A fork of sqlx which fixes the way structs are populated.

Because of the way that sqlx builds the mapping of field name to field address, by the time you Scan into a struct, it no longer knows whether or not a name was encountered twice during its traversal of the struct tree. So unlike Go, StructScan will choose the "first" field encountered which has that name.

This fork fixes this very annoying behaviour (which in my opinion makes the entire library broken). It is now possible to do the following, despite the fact that both structs have duplicated fields called ID and Title:

type Blog struct {
    ID    uint
    Title string
}

type Post struct {
    ID     uint
    BlogID uint
    Title  string
}

type PostAndBlog {
    Post
    Blog
}

var posts []PostAndBlog
if err := database.DB.Select(&posts,
    `SELECT post.*, blog.*
     FROM post
     JOIN blog ON blog.id = post.blog_id`); err != nil {
     panic(err)
 }

There is only a single caveat: please remember to embed structs in the same order in which they are selected in the database query. As you can see in the above example Blog is embedded in the struct after Post and it is also selected second in the SQL query. It is possible to embed any number of structs.

Disclaimer

This fix was created quickly and without much though put into it, it is possible that it breaks other features of the library without my knowledge.

Documentation

Overview

Package sqlx provides general purpose extensions to database/sql.

It is intended to seamlessly wrap database/sql and provide convenience methods which are useful in the development of database driven applications. None of the underlying database/sql methods are changed. Instead all extended behavior is implemented through new methods defined on wrapper types.

Additions include scanning into structs, named query support, rebinding queries for different drivers, convenient shorthands for common error handling and more.

Index

Constants

View Source 
const (
	UNKNOWN = iota
	QUESTION
	DOLLAR
	NAMED
)

Bindvar types supported by Rebind, BindMap and BindStruct.

Variables

View Source 
var NameMapper = strings.ToLower

NameMapper is used to map column names to struct field names. By default, it uses strings.ToLower to lowercase struct field names. It can be set to whatever you want, but it is encouraged to be set before sqlx is used as name-to-field mappings are cached after first use on a type.

Functions

func BindNamed 

func BindNamed(bindType int, query string, arg interface{}) (string, []interface{}, error)

BindNamed binds a struct or a map to a query with named parameters. DEPRECATED: use sqlx.Named` instead of this, it may be removed in future.

func BindType 

func BindType(driverName string) int

BindType returns the bindtype for a given database given a drivername.

func Get 

func Get(q Queryer, dest interface{}, query string, args ...interface{}) error

Get does a QueryRow using the provided Queryer, and scans the resulting row to dest. If dest is scannable, the result must only have one column. Otherwise, StructScan is used. Get will return sql.ErrNoRows like row.Scan would. Any placeholder parameters are replaced with supplied args. An error is returned if the result set is empty.

func In 

func In(query string, args ...interface{}) (string, []interface{}, error)

In expands slice values in args, returning the modified query string and a new arg list that can be executed by a database. The `query` should use the `?` bindVar. The return value uses the `?` bindVar.

func LoadFile 

func LoadFile(e Execer, path string) (*sql.Result, error)

LoadFile exec's every statement in a file (as a single call to Exec). LoadFile may return a nil *sql.Result if errors are encountered locating or reading the file at path. LoadFile reads the entire file into memory, so it is not suitable for loading large data dumps, but can be useful for initializing schemas or loading indexes.

FIXME: this does not really work with multi-statement files for mattn/go-sqlite3 or the go-mysql-driver/mysql drivers; pq seems to be an exception here. Detecting this by requiring something with DriverName() and then attempting to split the queries will be difficult to get right, and its current driver-specific behavior is deemed at least not complex in its incorrectness.

func MapScan 

func MapScan(r ColScanner, dest map[string]interface{}) error

MapScan scans a single Row into the dest map[string]interface{}. Use this to get results for SQL that might not be under your control (for instance, if you're building an interface for an SQL server that executes SQL from input). Please do not use this as a primary interface! This will modify the map sent to it in place, so reuse the same map with care. Columns which occur more than once in the result will overwrite each other!

func MustExec 

func MustExec(e Execer, query string, args ...interface{}) sql.Result

MustExec execs the query using e and panics if there was an error. Any placeholder parameters are replaced with supplied args.

func Named 

func Named(query string, arg interface{}) (string, []interface{}, error)

Named takes a query using named parameters and an argument and returns a new query with a list of args that can be executed by a database. The return value uses the `?` bindvar.

func NamedExec 

func NamedExec(e Ext, query string, arg interface{}) (sql.Result, error)

NamedExec uses BindStruct to get a query executable by the driver and then runs Exec on the result. Returns an error from the binding or the query excution itself.

func Rebind 

func Rebind(bindType int, query string) string

Rebind a query from the default bindtype (QUESTION) to the target bindtype.

func Select 

func Select(q Queryer, dest interface{}, query string, args ...interface{}) error

Select executes a query using the provided Queryer, and StructScans each row into dest, which must be a slice. If the slice elements are scannable, then the result set must have only one column. Otherwise, StructScan is used. The *sql.Rows are closed automatically. Any placeholder parameters are replaced with supplied args.

func SliceScan 

func SliceScan(r ColScanner) ([]interface{}, error)

SliceScan a row, returning a []interface{} with values similar to MapScan. This function is primarily intended for use where the number of columns is not known. Because you can pass an []interface{} directly to Scan, it's recommended that you do that as it will not have to allocate new slices per row.

func StructScan 

func StructScan(rows rowsi, dest interface{}) error

StructScan all rows from an sql.Rows or an sqlx.Rows into the dest slice. StructScan will scan in the entire rows result, so if you do not want to allocate structs for the entire result, use Queryx and see sqlx.Rows.StructScan. If rows is sqlx.Rows, it will use its mapper, otherwise it will use the default.

Types

type ColScanner 

type ColScanner interface {
	Columns() ([]string, error)
	Scan(dest ...interface{}) error
	Err() error
}

ColScanner is an interface used by MapScan and SliceScan

type DB 

type DB struct {
	*sql.DB

	Mapper *reflectx.Mapper
	// contains filtered or unexported fields
}

DB is a wrapper around sql.DB which keeps track of the driverName upon Open, used mostly to automatically bind named queries using the right bindvars.

func Connect 

func Connect(driverName, dataSourceName string) (*DB, error)

Connect to a database and verify with a ping.

func MustConnect 

func MustConnect(driverName, dataSourceName string) *DB

MustConnect connects to a database and panics on error.

func MustOpen 

func MustOpen(driverName, dataSourceName string) *DB

MustOpen is the same as sql.Open, but returns an *sqlx.DB instead and panics on error.

func NewDb 

func NewDb(db *sql.DB, driverName string) *DB

NewDb returns a new sqlx DB wrapper for a pre-existing *sql.DB. The driverName of the original database is required for named query support.

func Open 

func Open(driverName, dataSourceName string) (*DB, error)

Open is the same as sql.Open, but returns an *sqlx.DB instead.

func (*DB) Beginx 

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

Beginx begins a transaction and returns an *sqlx.Tx instead of an *sql.Tx.

func (*DB) BindNamed 

func (db *DB) BindNamed(query string, arg interface{}) (string, []interface{}, error)

BindNamed binds a query using the DB driver's bindvar type.

func (*DB) DriverName 

func (db *DB) DriverName() string

DriverName returns the driverName passed to the Open function for this DB.

func (*DB) Get 

func (db *DB) Get(dest interface{}, query string, args ...interface{}) error

Get using this DB. Any placeholder parameters are replaced with supplied args. An error is returned if the result set is empty.

func (*DB) MapperFunc 

func (db *DB) MapperFunc(mf func(string) string)

MapperFunc sets a new mapper for this db using the default sqlx struct tag and the provided mapper function.

func (*DB) MustBegin 

func (db *DB) MustBegin() *Tx

MustBegin starts a transaction, and panics on error. Returns an *sqlx.Tx instead of an *sql.Tx.

func (*DB) MustExec 

func (db *DB) MustExec(query string, args ...interface{}) sql.Result

MustExec (panic) runs MustExec using this database. Any placeholder parameters are replaced with supplied args.

func (*DB) NamedExec 

func (db *DB) NamedExec(query string, arg interface{}) (sql.Result, error)

NamedExec using this DB. Any named placeholder parameters are replaced with fields from arg.

func (*DB) NamedQuery 

func (db *DB) NamedQuery(query string, arg interface{}) (*Rows, error)

NamedQuery using this DB. Any named placeholder parameters are replaced with fields from arg.

func (*DB) PrepareNamed 

func (db *DB) PrepareNamed(query string) (*NamedStmt, error)

PrepareNamed returns an sqlx.NamedStmt

func (*DB) Preparex 

func (db *DB) Preparex(query string) (*Stmt, error)

Preparex returns an sqlx.Stmt instead of a sql.Stmt

func (*DB) QueryRowx 

func (db *DB) QueryRowx(query string, args ...interface{}) *Row

QueryRowx queries the database and returns an *sqlx.Row. Any placeholder parameters are replaced with supplied args.

func (*DB) Queryx 

func (db *DB) Queryx(query string, args ...interface{}) (*Rows, error)

Queryx queries the database and returns an *sqlx.Rows. Any placeholder parameters are replaced with supplied args.

func (*DB) Rebind 

func (db *DB) Rebind(query string) string

Rebind transforms a query from QUESTION to the DB driver's bindvar type.

func (*DB) Select 

func (db *DB) Select(dest interface{}, query string, args ...interface{}) error

Select using this DB. Any placeholder parameters are replaced with supplied args.

func (*DB) Unsafe 

func (db *DB) Unsafe() *DB

Unsafe returns a version of DB which will silently succeed to scan when columns in the SQL result have no fields in the destination struct. sqlx.Stmt and sqlx.Tx which are created from this DB will inherit its safety behavior.

type Execer 

type Execer interface {
	Exec(query string, args ...interface{}) (sql.Result, error)
}

Execer is an interface used by MustExec and LoadFile

type Ext 

type Ext interface {
	Queryer
	Execer
	// contains filtered or unexported methods
}

Ext is a union interface which can bind, query, and exec, used by NamedQuery and NamedExec.

type NamedStmt 

type NamedStmt struct {
	Params      []string
	QueryString string
	Stmt        *Stmt
}

NamedStmt is a prepared statement that executes named queries. Prepare it how you would execute a NamedQuery, but pass in a struct or map when executing.

func (*NamedStmt) Close 

func (n *NamedStmt) Close() error

Close closes the named statement.

func (*NamedStmt) Exec 

func (n *NamedStmt) Exec(arg interface{}) (sql.Result, error)

Exec executes a named statement using the struct passed. Any named placeholder parameters are replaced with fields from arg.

func (*NamedStmt) Get 

func (n *NamedStmt) Get(dest interface{}, arg interface{}) error

Get using this NamedStmt Any named placeholder parameters are replaced with fields from arg.

func (*NamedStmt) MustExec 

func (n *NamedStmt) MustExec(arg interface{}) sql.Result

MustExec execs a NamedStmt, panicing on error Any named placeholder parameters are replaced with fields from arg.

func (*NamedStmt) Query 

func (n *NamedStmt) Query(arg interface{}) (*sql.Rows, error)

Query executes a named statement using the struct argument, returning rows. Any named placeholder parameters are replaced with fields from arg.

func (*NamedStmt) QueryRow 

func (n *NamedStmt) QueryRow(arg interface{}) *Row

QueryRow executes a named statement against the database. Because sqlx cannot create a *sql.Row with an error condition pre-set for binding errors, sqlx returns a *sqlx.Row instead. Any named placeholder parameters are replaced with fields from arg.

func (*NamedStmt) QueryRowx 

func (n *NamedStmt) QueryRowx(arg interface{}) *Row

QueryRowx this NamedStmt. Because of limitations with QueryRow, this is an alias for QueryRow. Any named placeholder parameters are replaced with fields from arg.

func (*NamedStmt) Queryx 

func (n *NamedStmt) Queryx(arg interface{}) (*Rows, error)

Queryx using this NamedStmt Any named placeholder parameters are replaced with fields from arg.

func (*NamedStmt) Select 

func (n *NamedStmt) Select(dest interface{}, arg interface{}) error

Select using this NamedStmt Any named placeholder parameters are replaced with fields from arg.

func (*NamedStmt) Unsafe 

func (n *NamedStmt) Unsafe() *NamedStmt

Unsafe creates an unsafe version of the NamedStmt

type Preparer 

type Preparer interface {
	Prepare(query string) (*sql.Stmt, error)
}

Preparer is an interface used by Preparex.

type Queryer 

type Queryer interface {
	Query(query string, args ...interface{}) (*sql.Rows, error)
	Queryx(query string, args ...interface{}) (*Rows, error)
	QueryRowx(query string, args ...interface{}) *Row
}

Queryer is an interface used by Get and Select

type Row 

type Row struct {
	Mapper *reflectx.Mapper
	// contains filtered or unexported fields
}

Row is a reimplementation of sql.Row in order to gain access to the underlying sql.Rows.Columns() data, necessary for StructScan.

func (*Row) Columns 

func (r *Row) Columns() ([]string, error)

Columns returns the underlying sql.Rows.Columns(), or the deferred error usually returned by Row.Scan()

func (*Row) Err 

func (r *Row) Err() error

Err returns the error encountered while scanning.

func (*Row) MapScan 

func (r *Row) MapScan(dest map[string]interface{}) error

MapScan using this Rows.

func (*Row) Scan 

func (r *Row) Scan(dest ...interface{}) error

Scan is a fixed implementation of sql.Row.Scan, which does not discard the underlying error from the internal rows object if it exists.

func (*Row) SliceScan 

func (r *Row) SliceScan() ([]interface{}, error)

SliceScan using this Rows.

func (*Row) StructScan 

func (r *Row) StructScan(dest interface{}) error

StructScan a single Row into dest.

type Rows 

type Rows struct {
	*sql.Rows

	Mapper *reflectx.Mapper
	// contains filtered or unexported fields
}

Rows is a wrapper around sql.Rows which caches costly reflect operations during a looped StructScan

func NamedQuery 

func NamedQuery(e Ext, query string, arg interface{}) (*Rows, error)

NamedQuery binds a named query and then runs Query on the result using the provided Ext (sqlx.Tx, sqlx.Db). It works with both structs and with map[string]interface{} types.

func (*Rows) MapScan 

func (r *Rows) MapScan(dest map[string]interface{}) error

MapScan using this Rows.

func (*Rows) SliceScan 

func (r *Rows) SliceScan() ([]interface{}, error)

SliceScan using this Rows.

func (*Rows) StructScan 

func (r *Rows) StructScan(dest interface{}) error

StructScan is like sql.Rows.Scan, but scans a single Row into a single Struct. Use this and iterate over Rows manually when the memory load of Select() might be prohibitive. *Rows.StructScan caches the reflect work of matching up column positions to fields to avoid that overhead per scan, which means it is not safe to run StructScan on the same Rows instance with different struct types.

type Stmt 

type Stmt struct {
	*sql.Stmt

	Mapper *reflectx.Mapper
	// contains filtered or unexported fields
}

Stmt is an sqlx wrapper around sql.Stmt with extra functionality

func Preparex 

func Preparex(p Preparer, query string) (*Stmt, error)

Preparex prepares a statement.

func (*Stmt) Get 

func (s *Stmt) Get(dest interface{}, args ...interface{}) error

Get using the prepared statement. Any placeholder parameters are replaced with supplied args. An error is returned if the result set is empty.

func (*Stmt) MustExec 

func (s *Stmt) MustExec(args ...interface{}) sql.Result

MustExec (panic) using this statement. Note that the query portion of the error output will be blank, as Stmt does not expose its query. Any placeholder parameters are replaced with supplied args.

func (*Stmt) QueryRowx 

func (s *Stmt) QueryRowx(args ...interface{}) *Row

QueryRowx using this statement. Any placeholder parameters are replaced with supplied args.

func (*Stmt) Queryx 

func (s *Stmt) Queryx(args ...interface{}) (*Rows, error)

Queryx using this statement. Any placeholder parameters are replaced with supplied args.

func (*Stmt) Select 

func (s *Stmt) Select(dest interface{}, args ...interface{}) error

Select using the prepared statement. Any placeholder parameters are replaced with supplied args.

func (*Stmt) Unsafe 

func (s *Stmt) Unsafe() *Stmt

Unsafe returns a version of Stmt which will silently succeed to scan when columns in the SQL result have no fields in the destination struct.

type Tx 

type Tx struct {
	*sql.Tx

	Mapper *reflectx.Mapper
	// contains filtered or unexported fields
}

Tx is an sqlx wrapper around sql.Tx with extra functionality

func (*Tx) BindNamed 

func (tx *Tx) BindNamed(query string, arg interface{}) (string, []interface{}, error)

BindNamed binds a query within a transaction's bindvar type.

func (*Tx) DriverName 

func (tx *Tx) DriverName() string

DriverName returns the driverName used by the DB which began this transaction.

func (*Tx) Get 

func (tx *Tx) Get(dest interface{}, query string, args ...interface{}) error

Get within a transaction. Any placeholder parameters are replaced with supplied args. An error is returned if the result set is empty.

func (*Tx) MustExec 

func (tx *Tx) MustExec(query string, args ...interface{}) sql.Result

MustExec runs MustExec within a transaction. Any placeholder parameters are replaced with supplied args.

func (*Tx) NamedExec 

func (tx *Tx) NamedExec(query string, arg interface{}) (sql.Result, error)

NamedExec a named query within a transaction. Any named placeholder parameters are replaced with fields from arg.

func (*Tx) NamedQuery 

func (tx *Tx) NamedQuery(query string, arg interface{}) (*Rows, error)

NamedQuery within a transaction. Any named placeholder parameters are replaced with fields from arg.

func (*Tx) NamedStmt 

func (tx *Tx) NamedStmt(stmt *NamedStmt) *NamedStmt

NamedStmt returns a version of the prepared statement which runs within a transaction.

func (*Tx) PrepareNamed 

func (tx *Tx) PrepareNamed(query string) (*NamedStmt, error)

PrepareNamed returns an sqlx.NamedStmt

func (*Tx) Preparex 

func (tx *Tx) Preparex(query string) (*Stmt, error)

Preparex a statement within a transaction.

func (*Tx) QueryRowx 

func (tx *Tx) QueryRowx(query string, args ...interface{}) *Row

QueryRowx within a transaction. Any placeholder parameters are replaced with supplied args.

func (*Tx) Queryx 

func (tx *Tx) Queryx(query string, args ...interface{}) (*Rows, error)

Queryx within a transaction. Any placeholder parameters are replaced with supplied args.

func (*Tx) Rebind 

func (tx *Tx) Rebind(query string) string

Rebind a query within a transaction's bindvar type.

func (*Tx) Select 

func (tx *Tx) Select(dest interface{}, query string, args ...interface{}) error

Select within a transaction. Any placeholder parameters are replaced with supplied args.

func (*Tx) Stmtx 

func (tx *Tx) Stmtx(stmt interface{}) *Stmt

Stmtx returns a version of the prepared statement which runs within a transaction. Provided stmt can be either *sql.Stmt or *sqlx.Stmt.

func (*Tx) Unsafe 

func (tx *Tx) Unsafe() *Tx

Unsafe returns a version of Tx which will silently succeed to scan when columns in the SQL result have no fields in the destination struct.

Source Files

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Directories

Path Synopsis
Package reflectx implements extensions to the standard reflect lib suitable for implementing marshalling and unmarshalling packages.
 Package reflectx implements extensions to the standard reflect lib suitable for implementing marshalling and unmarshalling packages.

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