go-gorm-example

Summary

• model can extend gorm.Model, if extend gorm.Model will inject field ID, CreatedAt, UpdatedAt, and DeletedAt
• ID is primary key, but you can add custom ID using tag primary_key; example : gorm:"primary_key"
• table name using pluralized you create struct 'User' will create table 'users', but you also can make custom table name or make singular table name using db.SingularTable(true)
• column name will use snake case but you can override using tag column; example : gorm:"column:beast_id"
• for model has DeletedAt will delete as soft delete
• if wanna delete permanently can do by db.Unscoped().Delete(&order)
• support several database : mysql, postgre, sqlite, mssql
• create record; will return true if primary key is blank, if already exist will return false (for same object)
• default values can set by tag default; example : gorm:"default:'this is default value'"
• support plain SQL and CRUD interface; example : Create, First, Take, Last, Find
• plain SQL using Where method
• support null value using pointer or scaner/valuer varible example : sql.NullInt64, sql.NullBool, sql.NullFloat64, sql.NullString, etc sql.Nullxxxx
• support transaction
• support hook (Before/After Create/Save/Update/Delete/Find)
• support scope for filtering
• support migration, AutoMigrate will ONLY create tables, missing columns and missing indexes, and WON’T change existing column’s type or delete unused columns to protect your data : example db.AutoMigrate(&User{})
• cascade can define using tag OnUpdate, OnDelete example gorm:"ForeignKey:User.ID;OnUpdate:Cascade;OnDelete:Cascade"

Associations (relationship)

The relationship defines how the structs or models interact with each other

• "belongs to" relationship
• "has one" / "one to one" relationship
• "has many" / "one to many" relationship
• "many to many" relationship

sources

• https://gorm.io/docs/index.html
• https://jinzhu.me/gorm/
• https://www.mindbowser.com/golang-go-with-gorm/
• https://medium.com/aubergine-solutions/how-i-handled-null-possible-values-from-database-rows-in-golang-521fb0ee267
• http://blog.ralch.com/tutorial/golang-object-relation-mapping-with-gorm/
• http://learningprogramming.net/golang/gorm/call-stored-procedure-with-parameters-in-gorm/