250 lines
6.4 KiB
Go
250 lines
6.4 KiB
Go
// Copyright 2013 - 2016 The XORM Authors. All rights reserved.
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// Use of this source code is governed by a BSD
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// license that can be found in the LICENSE file.
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/*
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Package xorm is a simple and powerful ORM for Go.
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# Installation
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Make sure you have installed Go 1.11+ and then:
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go get xorm.io/xorm
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# Create Engine
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Firstly, we should create an engine for a database
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engine, err := xorm.NewEngine(driverName, dataSourceName)
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Method NewEngine's parameters are the same as sql.Open which depend drivers' implementation.
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Generally, one engine for an application is enough. You can define it as a package variable.
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# Raw Methods
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XORM supports raw SQL execution:
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1. query with a SQL string, the returned results is []map[string][]byte
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results, err := engine.Query("select * from user")
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2. query with a SQL string, the returned results is []map[string]string
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results, err := engine.QueryString("select * from user")
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3. query with a SQL string, the returned results is []map[string]interface{}
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results, err := engine.QueryInterface("select * from user")
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4. execute with a SQL string, the returned results
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affected, err := engine.Exec("update user set .... where ...")
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# ORM Methods
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There are 8 major ORM methods and many helpful methods to use to operate database.
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1. Insert one or multiple records to database
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affected, err := engine.Insert(&struct)
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// INSERT INTO struct () values ()
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affected, err := engine.Insert(&struct1, &struct2)
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// INSERT INTO struct1 () values ()
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// INSERT INTO struct2 () values ()
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affected, err := engine.Insert(&sliceOfStruct)
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// INSERT INTO struct () values (),(),()
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affected, err := engine.Insert(&struct1, &sliceOfStruct2)
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// INSERT INTO struct1 () values ()
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// INSERT INTO struct2 () values (),(),()
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2. Query one record or one variable from database
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has, err := engine.Get(&user)
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// SELECT * FROM user LIMIT 1
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var id int64
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has, err := engine.Table("user").Where("name = ?", name).Get(&id)
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// SELECT id FROM user WHERE name = ? LIMIT 1
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var id int64
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var name string
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has, err := engine.Table(&user).Cols("id", "name").Get(&id, &name)
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// SELECT id, name FROM user LIMIT 1
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3. Query multiple records from database
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var sliceOfStructs []Struct
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err := engine.Find(&sliceOfStructs)
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// SELECT * FROM user
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var mapOfStructs = make(map[int64]Struct)
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err := engine.Find(&mapOfStructs)
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// SELECT * FROM user
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var int64s []int64
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err := engine.Table("user").Cols("id").Find(&int64s)
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// SELECT id FROM user
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4. Query multiple records and record by record handle, there two methods, one is Iterate,
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another is Rows
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err := engine.Iterate(new(User), func(i int, bean interface{}) error {
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// do something
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})
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// SELECT * FROM user
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rows, err := engine.Rows(...)
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// SELECT * FROM user
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defer rows.Close()
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bean := new(Struct)
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for rows.Next() {
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err = rows.Scan(bean)
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}
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or
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rows, err := engine.Cols("name", "age").Rows(...)
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// SELECT * FROM user
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defer rows.Close()
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for rows.Next() {
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var name string
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var age int
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err = rows.Scan(&name, &age)
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}
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5. Update one or more records
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affected, err := engine.ID(...).Update(&user)
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// UPDATE user SET ...
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6. Delete one or more records, Delete MUST has condition
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affected, err := engine.Where(...).Delete(&user)
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// DELETE FROM user Where ...
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7. Count records
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counts, err := engine.Count(&user)
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// SELECT count(*) AS total FROM user
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counts, err := engine.SQL("select count(*) FROM user").Count()
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// select count(*) FROM user
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8. Sum records
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sumFloat64, err := engine.Sum(&user, "id")
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// SELECT sum(id) from user
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sumFloat64s, err := engine.Sums(&user, "id1", "id2")
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// SELECT sum(id1), sum(id2) from user
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sumInt64s, err := engine.SumsInt(&user, "id1", "id2")
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// SELECT sum(id1), sum(id2) from user
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# Conditions
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The above 8 methods could use with condition methods chainable.
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Notice: the above 8 methods should be the last chainable method.
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1. ID, In
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engine.ID(1).Get(&user) // for single primary key
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// SELECT * FROM user WHERE id = 1
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engine.ID(schemas.PK{1, 2}).Get(&user) // for composite primary keys
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// SELECT * FROM user WHERE id1 = 1 AND id2 = 2
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engine.In("id", 1, 2, 3).Find(&users)
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// SELECT * FROM user WHERE id IN (1, 2, 3)
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engine.In("id", []int{1, 2, 3}).Find(&users)
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// SELECT * FROM user WHERE id IN (1, 2, 3)
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2. Where, And, Or
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engine.Where().And().Or().Find()
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// SELECT * FROM user WHERE (.. AND ..) OR ...
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3. OrderBy, Asc, Desc
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engine.Asc().Desc().Find()
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// SELECT * FROM user ORDER BY .. ASC, .. DESC
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engine.OrderBy().Find()
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// SELECT * FROM user ORDER BY ..
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4. Limit, Top
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engine.Limit().Find()
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// SELECT * FROM user LIMIT .. OFFSET ..
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engine.Top(5).Find()
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// SELECT TOP 5 * FROM user // for mssql
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// SELECT * FROM user LIMIT .. OFFSET 0 //for other databases
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5. SQL, let you custom SQL
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var users []User
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engine.SQL("select * from user").Find(&users)
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6. Cols, Omit, Distinct
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var users []*User
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engine.Cols("col1, col2").Find(&users)
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// SELECT col1, col2 FROM user
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engine.Cols("col1", "col2").Where().Update(user)
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// UPDATE user set col1 = ?, col2 = ? Where ...
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engine.Omit("col1").Find(&users)
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// SELECT col2, col3 FROM user
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engine.Omit("col1").Insert(&user)
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// INSERT INTO table (non-col1) VALUES ()
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engine.Distinct("col1").Find(&users)
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// SELECT DISTINCT col1 FROM user
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7. Join, GroupBy, Having
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engine.GroupBy("name").Having("name='xlw'").Find(&users)
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//SELECT * FROM user GROUP BY name HAVING name='xlw'
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engine.Join("LEFT", "userdetail", "user.id=userdetail.id").Find(&users)
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//SELECT * FROM user LEFT JOIN userdetail ON user.id=userdetail.id
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# Builder
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xorm could work with xorm.io/builder directly.
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1. With Where
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var cond = builder.Eq{"a":1, "b":2}
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engine.Where(cond).Find(&users)
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2. With In
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var subQuery = builder.Select("name").From("group")
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engine.In("group_name", subQuery).Find(&users)
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3. With Join
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var subQuery = builder.Select("name").From("group")
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engine.Join("INNER", subQuery, "group.id = user.group_id").Find(&users)
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4. With SetExprs
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var subQuery = builder.Select("name").From("group")
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engine.ID(1).SetExprs("name", subQuery).Update(new(User))
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5. With SQL
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var query = builder.Select("name").From("group")
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results, err := engine.SQL(query).Find(&groups)
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6. With Query
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var query = builder.Select("name").From("group")
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results, err := engine.Query(query)
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results, err := engine.QueryString(query)
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results, err := engine.QueryInterface(query)
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7. With Exec
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var query = builder.Insert("a, b").Into("table1").Select("b, c").From("table2")
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results, err := engine.Exec(query)
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More usage, please visit http://xorm.io/docs
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*/
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package xorm
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