Question

1.1.1. 删除/软删除

警告删除记录时，需要确保其主要字段具有值，GORM将使用主键删除记录，如果主要字段为空，GORM将删除模型的所有记录

    // 删除存在的记录
    db.Delete(&email)
    //// DELETE from emails where id=10;

    // 为Delete语句添加额外的SQL选项
    db.Set("gorm:delete_option", "OPTION (OPTIMIZE FOR UNKNOWN)").Delete(&email)
    //// DELETE from emails where id=10 OPTION (OPTIMIZE FOR UNKNOWN);

1.1.2. 批量删除

删除所有匹配记录

    db.Where("email LIKE ?", "%jinzhu%").Delete(Email{})
    //// DELETE from emails where email LIKE "%jinhu%";

    db.Delete(Email{}, "email LIKE ?", "%jinzhu%")
    //// DELETE from emails where email LIKE "%jinhu%";

1.1.3. 软删除

如果模型有DeletedAt字段，它将自动获得软删除功能！ 那么在调用Delete时不会从数据库中永久删除，而是只将字段DeletedAt的值设置为当前时间。

    db.Delete(&user)
    //// UPDATE users SET deleted_at="2013-10-29 10:23" WHERE id = 111;

    // 批量删除
    db.Where("age = ?", 20).Delete(&User{})
    //// UPDATE users SET deleted_at="2013-10-29 10:23" WHERE age = 20;

    // 软删除的记录将在查询时被忽略
    db.Where("age = 20").Find(&user)
    //// SELECT * FROM users WHERE age = 20 AND deleted_at IS NULL;

    // 使用Unscoped查找软删除的记录
    db.Unscoped().Where("age = 20").Find(&users)
    //// SELECT * FROM users WHERE age = 20;

    // 使用Unscoped永久删除记录
    db.Unscoped().Delete(&order)
    //// DELETE FROM orders WHERE id=10;