有 uniqueIndex 的情况下，AutoMigrate 再次执行会报错：Can't DROP 'xxx'; check that column/key exists

[ocean-gao]

GORM Playground Link

go-gorm/playground#733

Description

type User struct {
	EnglishName string `json:"englishName" gorm:"uniqueIndex:idx_english_name;column:englishName;type:varchar(100);comment:英文名;"`
}

执行

DB.AutoMigrate(&User{})

的时候，初次执行正常，再次执行报错：

ALTER TABLE t_users DROP FOREIGN KEY uni_t_users_english_name
AutoMigrate for table faild. err:Error 1091 (42000): Can't DROP 'uni_t_users_english_name'; check that column/key exists

实际上是没有这个外键的，但依然会drop这个外键。

预期结果：

判断此外键是否存在，存在再去执行 Drop 方法。

[smnilu]

是的，我也发生这样的报错

[eslizn]

同步更新下driver版本

[haoran-mc]

type PrivacyRule struct {
	gorm.Model
	Key        string `gorm:"not null;uniqueIndex:idx_privacy_rule_key;"`
	Pattern    string `gorm:"not null;"`
}

更新到最新版本 1.25.10 的 gorm 给出了错误：

time="2024-05-14T10:16:32+08:00" level=error msg="migrate failed: ERROR: constraint "uni_privacy_rules_key" of relation "privacy_rules" does not exist (SQLSTATE 42704)"

检查发现表里面有一个 constraint（不知道是哪个版本给生成了一个 idx_...... 的约束）：

Indexes:
    "privacy_rules_pkey" PRIMARY KEY, btree (id)
    "idx_privacy_rule_key" UNIQUE, btree (key)
    "idx_privacy_rules_deleted_at" btree (deleted_at)
    "idx_privacy_rules_key" UNIQUE CONSTRAINT, btree (key)  // → 生成了未指定的 CONSTRAINT

目前只知道在这个 commit 8fb9a31 只前的版本不会报错，这个 commit 之后的版本会报错。

[whatwewant]

发生错误 +1

 ERROR: constraint "uni_v1_dict_uuid" of relation "v1_dict" does not exist (SQLSTATE 42704)

[siosphere]

I'm facing this same issue. Any unique column I declare will AutoMigrate the first time, but then fail (with no changes) trying to drop a constraint that does not exist.

I'm using postgres/cockroackdb as the datastore

[davisfelipe]

I got same issue, I partially solved it by changing the version from v1.25.9 to v1.25.5.

[qaqhy]

连接mysql就更新这个驱动包
gorm.io/driver/mysql v1.5.6

连接postgres就更新这个驱动包
gorm.io/driver/postgres v1.5.7

执行下面的命令也可以
go get gorm.io/driver/mysql@latest
go get gorm.io/driver/postgres@latest