Model is data model for your application.
Usually, model will be mapped to database table by Object-relational mapper (ORM).


Kocha provides generator of model, so you can use kocha g model command to generate a model.

kocha g model NAME

For example:

kocha g model user name:string age:int

The above command will generate the following files.

|-- app
|   `-- model
|       `-- user.go
`-- db
    `-- config.go`  # if not generated yet.


package model

import (

type User struct {
    Id   int64  `db:"pk" json:"id"`
    Name string `json:"name"`
    Age  int    `json:"age"`



By default, Kocha is using genmai ORM.

Using ORM

First, you write the following import path to files where you use ORM.

import "appname/db"

Second, get an instance of ORM and will use it.

dbinst := db.Get("default")

db.Get can use in controllers, models as well as other Go files.

Also you can read generated file db/config.go for more information.

Database configuration

The configurations of databases are defined in db/config.go by default.
You can specify database driver and data source name to use by some environment variables.

KOCHA_DB_DRIVER to set the driver name of the database such as "mysql".
KOCHA_DB_DSN to set the data source name for the database such as "user:password@/dbname"

Note that these environment variables are used in run-time, not compile-time.

To change to different database configuration, run the your application such as follows:

KOCHA_DB_DRIVER="mysql" KOCHA_DB_DSN="user:password@/dbname" kocha run

Or if you run the your application built by kocha build or go build.

KOCHA_DB_DRIVER="mysql" KOCHA_DB_DSN="user:password@/dbname" appname

This method is inspired by config of The Twelve-Factor App.


Kocha also supports database migration.
To generate a migration file, use kocha g migration command.

kocha g migration NAME

For example:

kocha g migration create_user_table

The above command will generate the following files.

`-- db
    `-- migration
        |-- 20140312091159_create_user_table.go
        `-- init.go

Where 20140312091159 is the timestamp of when generated that.
It is different each time it is generated.


package migration

import ""

func (m *Migration) Up_20140312091159_CreateUserTable(tx *genmai.DB) {
    // FIXME: Update database schema and/or insert seed data.

func (m *Migration) Down_20140312091159_CreateUserTable(tx *genmai.DB) {
    // FIXME: Revert the change done by Up_20140312091159_CreateUserTable.

A generated file has two methods for migration.
The method names start with Up_ are for forward migration, and Down_ are for backward migration.
If panic in these methods, Kocha will rollback the transaction of that migration.

You should write migration codes in those methods. Then type the following command to do migration:

kocha migrate up

If you want to rollback the migration, type the following command:

kocha migrate down

By default, kocha migrate up run the all migrations and kocha migrate down rollback the one of the most recent migration.