- 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.
- All struct fields are nullable by default and zero values (empty string, 0, zero time) are marshalled as SQL
NULL.sql:",notnull"tag is used to reverse this behaviour. - Transactions.
- Prepared statements.
- Notifications using
LISTENandNOTIFY. - Copying data using
COPY FROMandCOPY TO. - Timeouts.
- Automatic connection pooling.
- 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 and updates.
- 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.
- Creating tables from structs.
- Pagination and URL filters helpers.
- Migrations.
- Sharding.
package pg_test
import (
"fmt"
"github.com/go-pg/pg"
"github.com/go-pg/pg/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",
})
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.
var story Story
err = db.Model(&story).
Column("story.*", "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{}, &Story{}} {
err := db.CreateTable(model, nil)
if err != nil {
return err
}
}
return nil
}