schema

README

schema

schema is a Go package providing access to database schema metadata, for database/sql drivers.

TODO more docs

Currently supporting the following database engines / SQL dialects:

• Microsoft SQL Server
• MySQL
• Oracle
• Postgres
• SQLite

For a list of supported drivers, and their capabilities with regards to sql.ColumnType support, see drivercaps

Installation

$ go get github.com/jimsmart/schema

import "github.com/jimsmart/schema"

Dependencies

• A supported database driver.
• Standard library.
• Ginkgo and Gomega if you wish to run the tests.
• Tests also require Docker Compose to be installed.

Example

See GoDocs for usage examples.

Documentation

GoDocs https://godoc.org/github.com/jimsmart/schema

Testing

Database services for testing against are hosted in Docker.

To bring up the database services: execute docker-compose up inside the project folder, and wait until all of the Docker services have completed their startup (i.e. there is no further output in the terminal), then open a second terminal. (In future one may choose to use docker-compose up -d instead)

To run the tests execute go test inside the project folder.

For a full coverage report, try:

$ go test -coverprofile=coverage.out && go tool cover -html=coverage.out

To shutdown the Docker services, execute docker-compose down -v inside the project folder.

License

Package schema is copyright 2018-2019 by Jim Smart and released under the BSD 3-Clause License

History

• v0.0.4: Improved error handling for unknown DB driver types. Test environment now uses Docker.
• v0.0.3: Minor code cleanups.
• v0.0.2: Added identifier escaping for methods that query sql.ColumnType.
• v0.0.1: Started using Go modules.
• 2019-11-04: Fix for renamed driver struct in github.com/mattn/go-oci8 (Oracle)
• 2019-11-04: Fix for renamed driver struct in github.com/denisenkom/go-mssqldb (MSSQL)

Documentation

Overview

Package schema provides access to database schema metadata, for database/sql drivers.

For further information about current driver support status, see https://github.com/jimsmart/schema

Table Metadata

The schema package works alongside database/sql and its underlying driver to provide schema metadata.

tnames, err := schema.TableNames(db)
	...
// tnames is []string
for i := range tnames {
	fmt.Printf("Table: %s\n", tnames[i])
}

// Output:
// Table: employee_tbl
// Table: department_tbl
// Table: sales_tbl

Both user permissions and current database/schema effect table visibility.

To query column type metadata for a single table, use schema.Table().

tcols, err := schema.Table(db, "employee_tbl")
	...
// tcols is []*sql.ColumnType
for i := range tcols {
	fmt.Printf("Column: %s %s\n", tcols[i].Name(), tcols[i].DatabaseTypeName())
}

// Output:
// Column: employee_id INTEGER
// Column: first_name TEXT
// Column: last_name TEXT
// Column: created_at TIMESTAMP

To query table names and column type metadata for all tables, use schema.Tables().

See also https://golang.org/pkg/database/sql/#ColumnType

Underlying driver support for column type metadata is implementation specific and somewhat variable.

View Metadata

The same metadata can also be queried for views.

Index

• func Table(db *sql.DB, name string) ([]*sql.ColumnType, error)
• func TableNames(db *sql.DB) ([]string, error)
• func Tables(db *sql.DB) (map[string][]*sql.ColumnType, error)
• func View(db *sql.DB, name string) ([]*sql.ColumnType, error)
• func ViewNames(db *sql.DB) ([]string, error)
• func Views(db *sql.DB) (map[string][]*sql.ColumnType, error)
• type UnknownDriverError
  • func (e UnknownDriverError) Error() string

Functions

func Table

func Table(db *sql.DB, name string) ([]*sql.ColumnType, error)

Table returns the column type metadata for the given table name.

func TableNames

func TableNames(db *sql.DB) ([]string, error)

TableNames returns a list of all table names in the current schema (not including system tables).

func Tables

func Tables(db *sql.DB) (map[string][]*sql.ColumnType, error)

Tables returns column type metadata for all tables in the current schema (not including system tables). The returned map is keyed by table name.

func View

func View(db *sql.DB, name string) ([]*sql.ColumnType, error)

View returns the column type metadata for the given view name.

func ViewNames

func ViewNames(db *sql.DB) ([]string, error)

ViewNames returns a list of all view names in the current schema (not including system views).

func Views

func Views(db *sql.DB) (map[string][]*sql.ColumnType, error)

Views returns column type metadata for all views in the current schema (not including system views). The returned map is keyed by view name.

Types

type UnknownDriverError

type UnknownDriverError struct {
	Driver string
}

UnknownDriverError is returned when there is no matching database driver type name in the driverDialect table.

Errors of this kind are caused by using an unsupported database driver/dialect, or if/when a database driver developer renames the type underlying calls to db.Driver().

func (UnknownDriverError) Error

func (e UnknownDriverError) Error() string

Error returns a formatted string description.