PostgreSQL client and ORM for Golang
Features
- Basic types: integers, floats, string, bool, time.Time, net.IP, net.IPNet.
- sql.NullBool, sql.NullString, sql.NullInt64, sql.NullFloat64 and pg.NullTime.
- sql.Scanner and sql/driver.Valuer interfaces.
- Structs, maps and arrays are marshalled as JSON by default.
- PostgreSQL multidimensional Arrays using array tag and Array wrapper.
- Hstore using hstore tag and Hstore wrapper.
- Composite types.
- All struct fields are nullable by default and zero values (empty string, 0, zero time, empty map or slice, nil ptr) are marshalled as SQL
NULL.pg:",notnull"is used to add SQLNOT NULLconstraint andpg:",use_zero"to allow Go zero values. - Transactions.
- Prepared statements.
- Notifications using
LISTENandNOTIFY. - Copying data using
COPY FROMandCOPY TO. - Timeouts and canceling queries using context.Context.
- Automatic connection pooling with circuit breaker support.
- Queries retries on network errors.
- Working with models using ORM and SQL.
- Scanning variables using ORM and SQL.
- SelectOrInsert using on-conflict.
- INSERT ... ON CONFLICT DO UPDATE using ORM.
- Bulk/batch inserts, updates, and deletes.
- Common table expressions using WITH and WrapWith.
- CountEstimate using
EXPLAINto get estimated number of matching rows. - ORM supports has one, belongs to, has many, and many to many with composite/multi-column primary keys.
- Soft deletes.
- Creating tables from structs.
- ForEach that calls a function for each row returned by the query without loading all rows into the memory.
- Works with PgBouncer in transaction pooling mode.
Ecosystem
- Migrations by vmihailenco and robinjoseph08.
- Sharding.
- Model generator from SQL tables.
- urlstruct to decode
url.Valuesinto structs.
Get Started
go-pg requires a Go version with Modules support and uses import versioning. So please make sure to initialize a Go module before installing go-pg:
go mod init github.com/my/repo
go get github.com/go-pg/pg/v9
Look & Feel
package pg_test
import (
"fmt"
"github.com/go-pg/pg/v9"
"github.com/go-pg/pg/v9/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
}
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.Insert(user1)
if err != nil {
panic(err)
}
err = db.Insert(&User{
Name: "root",
Emails: []string{"root1@root", "root2@root"},
})
if err != nil {
panic(err)
}
story1 := &Story{
Title: "Cool story",
AuthorId: user1.Id,
}
err = db.Insert(story1)
if err != nil {
panic(err)
}
// Select user by primary key.
user := &User{Id: user1.Id}
err = db.Select(user)
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]>>
}
func createSchema(db *pg.DB) error {
for _, model := range []interface{}{(*User)(nil), (*Story)(nil)} {
err := db.CreateTable(model, &orm.CreateTableOptions{
Temp: true,
})
if err != nil {
return err
}
}
return nil
}