使用SQL语句进行查询
- 使用 Raw SQL 查询,无需使用 ORM 表定义
- 多数据库,都可直接使用占位符号
?
,自动转换 - 查询时的参数,支持使用 Model Struct 和 Slice, Array
o := orm.NewOrm()
ids := []int{1, 2, 3}
var r RawSter
r = o.Raw("SELECT name FROM user WHERE id IN (?, ?, ?)", ids)
创建一个 RawSeter
o := orm.NewOrm()
var r RawSeter
r = o.Raw("UPDATE user SET name = ? WHERE name = ?", "testing", "slene")
// RawSeter raw query seter
// create From Ormer.Raw
// for example:
// sql := fmt.Sprintf("SELECT %sid%s,%sname%s FROM %suser%s WHERE id = ?",Q,Q,Q,Q,Q,Q)
// rs := Ormer.Raw(sql, 1)
type RawSeter interface {
// execute sql and get result
Exec() (sql.Result, error)
// query data and map to container
// for example:
// var name string
// var id int
// rs.QueryRow(&id,&name) // id==2 name=="slene"
QueryRow(containers ...interface{}) error
// query data rows and map to container
// var ids []int
// var names []int
// query = fmt.Sprintf("SELECT 'id','name' FROM %suser%s", Q, Q)
// num, err = dORM.Raw(query).QueryRows(&ids,&names) // ids=>{1,2},names=>{"nobody","slene"}
QueryRows(containers ...interface{}) (int64, error)
SetArgs(...interface{}) RawSeter
// query data to []map[string]interface
// see QuerySeter's Values
Values(container *[]Params, cols ...string) (int64, error)
// query data to [][]interface
// see QuerySeter's ValuesList
ValuesList(container *[]ParamsList, cols ...string) (int64, error)
// query data to []interface
// see QuerySeter's ValuesFlat
ValuesFlat(container *ParamsList, cols ...string) (int64, error)
// query all rows into map[string]interface with specify key and value column name.
// keyCol = "name", valueCol = "value"
// table data
// name | value
// total | 100
// found | 200
// to map[string]interface{}{
// "total": 100,
// "found": 200,
// }
RowsToMap(result *Params, keyCol, valueCol string) (int64, error)
// query all rows into struct with specify key and value column name.
// keyCol = "name", valueCol = "value"
// table data
// name | value
// total | 100
// found | 200
// to struct {
// Total int
// Found int
// }
RowsToStruct(ptrStruct interface{}, keyCol, valueCol string) (int64, error)
// return prepared raw statement for used in times.
// for example:
// pre, err := dORM.Raw("INSERT INTO tag (name) VALUES (?)").Prepare()
// r, err := pre.Exec("name1") // INSERT INTO tag (name) VALUES (`name1`)
Prepare() (RawPreparer, error)
}
Exec
执行 sql 语句,返回 sql.Result 对象
res, err := o.Raw("UPDATE user SET name = ?", "your").Exec()
if err == nil {
num, _ := res.RowsAffected()
fmt.Println("mysql row affected nums: ", num)
}
QueryRow
QueryRow 和 QueryRows 提供高级 sql mapper 功能
支持 struct
type User struct {
Id int
UserName string
}
var user User
err := o.Raw("SELECT id, user_name FROM user WHERE id = ?", 1).QueryRow(&user)
QueryRows
QueryRows 支持的对象还有 map 规则是和 QueryRow 一样的,但都是 slice
type User struct {
Id int
UserName string
}
var users []User
num, err := o.Raw("SELECT id, user_name FROM user WHERE id = ?", 1).QueryRows(&users)
if err == nil {
fmt.Println("user nums: ", num)
}
SetArgs
改变 Raw(sql, args…) 中的 args 参数,返回一个新的 RawSeter
用于单条 sql 语句,重复利用,替换参数然后执行。
res, err := r.SetArgs("arg1", "arg2").Exec()
res, err := r.SetArgs("arg1", "arg2").Exec()
...
Values / ValuesList / ValuesFlat
Raw SQL 查询获得的结果集 Value 为 string
类型,NULL 字段的值为空 ``
Values
返回结果集的 key => value 值
var maps []orm.Params
num, err := o.Raw("SELECT user_name FROM user WHERE status = ?", 1).Values(&maps)
if err == nil && num > 0 {
fmt.Println(maps[0]["user_name"]) // slene
}
ValuesList
返回结果集 slice
var lists []orm.ParamsList
num, err := o.Raw("SELECT user_name FROM user WHERE status = ?", 1).ValuesList(&lists)
if err == nil && num > 0 {
fmt.Println(lists[0][0]) // slene
}
ValuesFlat
返回单一字段的平铺 slice 数据
var list orm.ParamsList
num, err := o.Raw("SELECT id FROM user WHERE id < ?", 10).ValuesFlat(&list)
if err == nil && num > 0 {
fmt.Println(list) // []{"1","2","3",...}
}
RowsToMap
SQL 查询结果是这样
name | value |
---|---|
total | 100 |
found | 200 |
查询结果匹配到 map 里
res := make(orm.Params)
nums, err := o.Raw("SELECT name, value FROM options_table").RowsToMap(&res, "name", "value")
// res is a map[string]interface{}{
// "total": 100,
// "found": 200,
// }
RowsToStruct
SQL 查询结果是这样
name | value |
---|---|
total | 100 |
found | 200 |
查询结果匹配到 struct 里
type Options struct {
Total int
Found int
}
res := new(Options)
nums, err := o.Raw("SELECT name, value FROM options_table").RowsToStruct(res, "name", "value")
fmt.Println(res.Total) // 100
fmt.Println(res.Found) // 200
匹配支持的名称转换为 snake -> camel, eg: SELECT user_name … 需要你的 struct 中定义有 UserName
Prepare
用于一次 prepare 多次 exec,以提高批量执行的速度。
p, err := o.Raw("UPDATE user SET name = ? WHERE name = ?").Prepare()
res, err := p.Exec("testing", "slene")
res, err = p.Exec("testing", "astaxie")
...
...
p.Close() // 别忘记关闭 statement