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| Original file line number | Diff line number | Diff line change |
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| @@ -1 +1,186 @@ | ||
| # gormx | ||
| # gormx | ||
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| `gormx` 是对 `gorm` 的高阶函数操作的简单封装 | ||
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| ## 使用 | ||
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| - 初始化 | ||
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| 调用 `New` 实例化一个新的数据库对象，自定义的参数通过 `Config` 传入 | ||
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| ```go | ||
| conf := &Config{ | ||
| Dialector: postgres.Open(dsn), //使用 postgres 驱动 | ||
| MaxIdleConn: 10, | ||
| MaxOpenConn: 10, | ||
| MaxLifetime: 1000, | ||
| Debug: false, | ||
| } | ||
| db, _ := New(conf, opts...) | ||
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| // 获取原始 gorm 对象 | ||
| // gormdb := db.DB() | ||
| ``` | ||
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| - 高阶函数构建 | ||
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| ```go | ||
| func WithName(name string) Option { | ||
| return func(db *gorm.DB) *gorm.DB { | ||
| return db.Where("name=?", name) | ||
| } | ||
| } | ||
| ``` | ||
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| - 创建记录 | ||
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| ```go | ||
| // 创建单条记录 | ||
| user := User{ | ||
| Nickname: "hello", | ||
| } | ||
| db.Insert(&user) | ||
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| // 创建多条记录 | ||
| var users []User | ||
| for i := 0; i < 2; i++ { | ||
| users = append(users, User{ | ||
| Nickname: fmt.Sprintf("hello %d", i), | ||
| Age: int64(i), | ||
| }) | ||
| } | ||
| db.Insert(users) | ||
| ``` | ||
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| - 查询单条记录 | ||
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| ```go | ||
| var user = User{ | ||
| Id: 1, | ||
| } | ||
| // model 中的 ID 需要是主键 | ||
| db.FindOne(&user) | ||
| //SQL: select * from test_users where id=1; | ||
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| // 带有 where 条件 | ||
| func WithName(name string) Option { | ||
| return func(db *gorm.DB) *gorm.DB { | ||
| return db.Where("name=?", name) | ||
| } | ||
| } | ||
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| var user User | ||
| db.FindOne(&user, WithName("hello")) | ||
| //SQL: select * from test_users where name='hello'; | ||
| ``` | ||
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| - 查询多条记录 | ||
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| ```go | ||
| var user []User | ||
| db.FindMany(&user, Pagination(1, 2)) | ||
| //SQL: select * from test_users limit 2; | ||
| ``` | ||
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| - 更新记录 | ||
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| ```go | ||
| // 更新不存在的记录，会返回 `ErrNoRowsAffected`，注意检查错误 | ||
| err = db.Model(&User{Id: -1}).Update("nickname", "hello world") | ||
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| // 更新单字段 | ||
| err = db.Model(&User{Id: 1}).Update("nickname", "hello world") | ||
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| // 使用struct更新多字段 | ||
| err = db.Updates(&User{ | ||
| Id: 1, | ||
| Nickname: "hello struct", | ||
| Age: 133, | ||
| }) | ||
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| // 使用 map 更新多字段 | ||
| err = db.Model(&User{Id: 1}).Updates(map[string]interface{}{ | ||
| "nickname": "hello map", | ||
| "age": "133", | ||
| }) | ||
| ``` | ||
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| - 删除记录 | ||
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| ```go | ||
| user := User{Id: 1} | ||
| err = db.Delete(&user) | ||
| ``` | ||
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| - 检查记录是否存在 | ||
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| ```go | ||
| exists, err := db.Exists(&User{ | ||
| Id: 1, | ||
| }) | ||
| // SQL: select exists(select * from test_users where id=1 limit 1); | ||
| ``` | ||
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| - 获取记录数 | ||
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| ```go | ||
| total, err := db.Model(&User{}).Count() | ||
| // SQL: SELECT count(*) FROM test_users; | ||
| ``` | ||
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| - SQL 执行 | ||
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| ```go | ||
| // 建表 | ||
| db.Exec("create table test_users (id serial primary key not null, nickname varchar(64) not null, age integer default 0);") | ||
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| ``` | ||
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| - SQL 查询 | ||
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| ```go | ||
| var ( | ||
| query = `select * from test_users where id=?` | ||
| args = []interface{}{1} | ||
| user User | ||
| ) | ||
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| // 执行查询 SQL 后再将数据映射到model 中 | ||
| db.Raw(query, args...).FindOne(&user) | ||
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| var myUser struct { | ||
| Id int64 | ||
| Nickname string | ||
| } | ||
| // 执行 SQL 后将数据映射到任意自定义对象 | ||
| db.Raw(query, args...).Scan(&myUser) | ||
| ``` | ||
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| - 上下文Context设置 | ||
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| ```go | ||
| // 请求之前都需要设置 Context，否则无法追踪调用链路 | ||
| db.WithContext(ctx).FindOne(...) | ||
| ``` | ||
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| - 事务 | ||
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| ```go | ||
| err := db.WithContext(ctx).Tx(func(tx *db) error { | ||
| if err := tx.Model(&User{Id: 1}).Update("nickname", "hello tx"); err != nil { | ||
| return err | ||
| } | ||
| user := User{ | ||
| Nickname: "hello tx insert", | ||
| Age: 133, | ||
| } | ||
| if err := tx.Insert(&user); err != nil { | ||
| return err | ||
| } | ||
| return nil | ||
| }) | ||
| ``` | ||
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| ## 最后 | ||
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| `gorm`对简单 `SQL` 操作比较好用，复杂的查询还得使用原生 `SQL`，所以不能满足使用的时候，取出 `gorm` 对象自己操作 `SQL` 就行了 |
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