model.md

Model

1 Creating your Model

To create a model for the table user in your database, create the UserModel class with the following syntax:

1. extends net.jkcode.jkmvc.orm.Orm class
2. define companion object as meta data
3. use property() to define delegate property

class UserModel(id:Int? = null): Orm(id) {
	// companion object is meta data
 	companion object m: OrmMeta(UserModel::class /* model class */, "User Model" /* model label */, "user" /* table name */, "id" /* table primary key */){}

	// delegate property
	public var id:Int by property()

	public var username:String by property()

	public var password:String by property()
}

2 Meta data

Meta data is the database information about this model, including database name, table name, primary key, etc.

Orm's meta data reprensents by class net.jkcode.jkmvc.orm.OrmMeta, which has the follow properties:

1. model class
2. model label, default is model name
3. table name, default is model name
4. primary key, , default is id
5. database name, which is defined in dataSources.yaml, default is default

When you create a net.jkcode.jkmvc.orm.OrmMeta object, you must pass these properties, just like:

OrmMeta(UserModel::class /* model class */, "User Model" /* model label */, "user" /* table name */, "id" /* table primary key */, "default" /* database name */){}

3 Bind meta data to model

For each model, you must define meta data in companion object.

companion object m: OrmMeta(UserModel::class, "User Model", "user", "id"){}

4 Auto generate model code

Jkmvc provide net.jkcode.jkmvc.util.ModelGenerator to generate model code

val generator = ModelGenerator("/home/shi/code/java/jkmvc/jkmvc-example/src/main/kotlin" /* code directory */, "net.jkcode.jkmvc.example.model" /* package */, "default" /* database name */, "shijianhang" /* author */)
generator.genenateModelFile("UserModel" /* model class name */, "用户模型" /* model label */, "user" /* table name */)

It will generate model code, according to the database and the table. And convert database column name to object's property name, according to configuration item columnUnderline and columnUpperCase in file dataSources.yaml.

The code is following

class UserModel(id:Int? = null): Orm(id) {
	// companion object is meta data
 	companion object m: OrmMeta(UserModel::class /* model class */, "User Model" /* model label */, "user" /* table name */, "id" /* table primary key */){}

	// delegate property
	public var id:Int by property()

	public var username:String by property()

	public var password:String by property()
}