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Ent

Any ORM or library is supported in Kratos project for data accessing. Please refer to the examples for integration.

Ent is an easy-to-use ORM which developed by Facebook. Here is a brief guide to use this library.

Install Ent

go install entgo.io/ent/cmd/ent

Create Schema

ent init User

This command will generate schema in project/ent/schema/ directory.

// <project>/ent/schema/user.go

package schema

import "entgo.io/ent"

// User holds the schema definition for the User entity.
type User struct {
ent.Schema
}

// Fields of the User.
func (User) Fields() []ent.Field {
return nil
}

// Edges of the User.
func (User) Edges() []ent.Edge {
return nil
}

Add two fields name、age to User table.

package schema

import (
"entgo.io/ent"
"entgo.io/ent/schema/field"
)

// Fields of the User.
func (User) Fields() []ent.Field {
return []ent.Field{
field.Int("age").
Positive(),
field.String("name").
Default("unknown"),
}
}

Run go generate:

go generate ./ent

Create DB Connection Client

First, create a new ent.Client. We use SQLite3 here for demonstration.

package main

import (
"context"
"log"

"<project>/ent"

_ "github.com/mattn/go-sqlite3"
)

func main() {
client, err := ent.Open("sqlite3", "file:ent?mode=memory&cache=shared&_fk=1")
if err != nil {
log.Fatalf("failed opening connection to sqlite: %v", err)
}
defer client.Close()
// Run the auto migration tool.
if err := client.Schema.Create(context.Background()); err != nil {
log.Fatalf("failed creating schema resources: %v", err)
}
}

To create a User in table.

func CreateUser(ctx context.Context, client *ent.Client) (*ent.User, error) {
u, err := client.User.
Create().
SetAge(30).
SetName("a8m").
Save(ctx)
if err != nil {
return nil, fmt.Errorf("failed creating user: %v", err)
}
log.Println("user was created: ", u)
return u, nil
}

References