How to set table links in gorm (golang)?

Question

There are 2 structures

type Student struct { Id uint64 `sql:"AUTO_INCREMENT" gorm:"primary_key"` Name string `sql:"size:80` } type Struct1 struct { Id uint64 `sql:"AUTO_INCREMENT" gorm:"primary_key"` StudentId Student //`gorm:"ForeignKey:Id"` Time time.Time `sql:"DEFAULT:current_timestamp"` Value int //Какие-нибудь значения }

I did the migration and the tables were created in the database

 db.AutoMigrate(&Student{}) db.AutoMigrate(&Struct1{})

But I want, that in a DB communications with cascade change too were created.
That is, now I have added student id 1, and the other table does not know about the existence of the Students table and you can write anything to StudentId.
How to register keys through gorm?

In the convention of names in go , ID used instead of Id .
StudentID must be an integer, and the reference to the structure is done separately.
Use @"мой ник" , not commenting on my posts, so that I could see the comment.

Accepted Answer · 2016-03-22T16:47:08

For example for such models

 // has_many Ys type X struct { gorm.Model } // belongs_to X type Y struct { gorm.Model XID uint }

In so

 db.Model(&Y{}).AddForeignKey("x_id", "xes (id)", "CASCADE", "CASCADE")

Respectively RESTRICT instead of CASCADE if necessary. Docks The first CASCADE works ON UPODATE second ON DELETE .

The resulting SQL will be

 ALTER TABLE "ys" -- к какой таблице добавляется ограничение ADD CONSTRAINT "ys_x_id_xes_id_foreign" -- имя ограничения FOREIGN KEY ("x_id") -- какая колонка будет внешним ключом (в таблице ys) REFERENCES xes (id) -- к какой таблице (к какой колонке) ON DELETE CASCADE -- при удалении ON UPDATE CASCADE; -- при обновлении

probably will need to update GORM with

 go get -u github.com/jinzhu/gorm

Remember that this restriction does not guarantee that Y will necessarily refer to X. To do this, add NOT NULL to x_id .
@RakzinRoman, I mean that x_id can remain NULL and the restriction will not work in this case.
Oooh .... how to take your code entirely, everything works, and he himself took parts a little bit everywhere .... Thank you
@ "Ivan Black" @Ivan Black Writes the relationship "xes" does not exist.
db.Model (& Y {}). AddForeignKey ("x_id", "xes (id)", "CASCADE", "CASCADE") - here we are binding the second table (Y) to the field x_id to the field X (id) table X field id.

How to set table links in gorm (golang)?

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