# ent是什么 ent是一个简单而又功能强大的Go语言实体框架，ent易于构建和维护应用程序与大数据模型。简而言之，ent是一款便于操作的orm框架 # installation `go get entgo.io/ent/cmd/ent` # 使用 ## 创建schema 在连接ent之前，我们首先需要创建schema，创建schema的作用类似django创建model，规定数据表字段，定义表名等 **cli创建model模板命令** ```shell ent init --target ``` `--target`目的是指定创建模板路径， `Model Name`必须使用驼峰命名法我们可以通过`ent init --target spec/schema Class Student`命令在`spec/schema`目录下创建两个模板，class.go和student.go 如下所示： ```go // spec/schema/class.go package schema import ( "entgo.io/ent" ) // Class holds the schema definition for the Class entity. type Class struct { ent.Schema } // Fields of the Class. func (Class) Fields() []ent.Field { return nil } // Edges of the Class. func (Class) Edges() []ent.Edge { return nil } ``` ```go // spec/schema/student.go package schema import ( "entgo.io/ent" ) // Student holds the schema definition for the Student entity. type Student struct { ent.Schema } // Fields of the Student. func (Student) Fields() []ent.Field { return nil } // Edges of the Student. func (Student) Edges() []ent.Edge { return nil } ``` ### 创建完整的数据结构我们在生成的模板内，将表字段添加进去 ```go // spec/schema/class.go package schema import ( "entgo.io/ent" "entgo.io/ent/dialect/entsql" "entgo.io/ent/schema" "entgo.io/ent/schema/edge" "entgo.io/ent/schema/field" ) // Class holds the schema definition for the Class entity. type Class struct { ent.Schema } // Fields of the Class. func (Class) Fields() []ent.Field { return []ent.Field{ field.String("name").MaxLen(50).Comment("名称"), field.Int("level").Comment("级别"), } } // Edges of the Class. func (Class) Edges() []ent.Edge { return []ent.Edge{ edge.To("student", Student.Type), } } func (Class) Annotations() []schema.Annotation { return []schema.Annotation{ entsql.Annotation{Table: "class"}, } } ``` ```go // spec/schema/student.go package schema import ( "entgo.io/ent" "entgo.io/ent/dialect/entsql" "entgo.io/ent/schema" "entgo.io/ent/schema/edge" "entgo.io/ent/schema/field" ) // Student holds the schema definition for the Student entity. type Student struct { ent.Schema } // Fields of the Student. func (Student) Fields() []ent.Field { return []ent.Field{ field.String("name").MaxLen(50).Comment("名称"), field.Bool("sex").Comment("性别"), field.Int("age").Comment("年龄"), field.Int("class_id").Comment("班级ID"), } } // Edges of the Student. func (Student) Edges() []ent.Edge { return []ent.Edge{ edge.From("class", Class.Type). Ref("student"). Unique(). Field("class_id"). Required(), } } func (Student) Annotations() []schema.Annotation { return []schema.Annotation{ entsql.Annotation{ Table: "student", }, } } ``` ### 生成代码基于schema的定义（字段，索引，边，配置）来生成对应的数据表操作代码 `ent generate --target