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// Copyright 2013 - 2016 The XORM Authors. All rights reserved.
// Use of this source code is governed by a BSD
// license that can be found in the LICENSE file.
/*
Package xorm is a simple and powerful ORM for Go.
Installation
Make sure you have installed Go 1.6+ and then:
go get github.com/go-xorm/xorm
Create Engine
Firstly, we should new an engine for a database
engine, err := xorm.NewEngine(driverName, dataSourceName)
Method NewEngine's parameters is the same as sql.Open. It depends
drivers' implementation.
Generally, one engine for an application is enough. You can set it as package variable.
Raw Methods
XORM also support raw SQL execution:
1. query a SQL string, the returned results is []map[string][]byte
results, err := engine.Query("select * from user")
2. execute a SQL string, the returned results
affected, err := engine.Exec("update user set .... where ...")
ORM Methods
There are 8 major ORM methods and many helpful methods to use to operate database.
1. Insert one or multiple records to database
affected, err := engine.Insert(&struct)
// INSERT INTO struct () values ()
affected, err := engine.Insert(&struct1, &struct2)
// INSERT INTO struct1 () values ()
// INSERT INTO struct2 () values ()
affected, err := engine.Insert(&sliceOfStruct)
// INSERT INTO struct () values (),(),()
affected, err := engine.Insert(&struct1, &sliceOfStruct2)
// INSERT INTO struct1 () values ()
// INSERT INTO struct2 () values (),(),()
2. Query one record or one variable from database
has, err := engine.Get(&user)
// SELECT * FROM user LIMIT 1
var id int64
has, err := engine.Table("user").Where("name = ?", name).Get(&id)
// SELECT id FROM user WHERE name = ? LIMIT 1
3. Query multiple records from database
var sliceOfStructs []Struct
err := engine.Find(&sliceOfStructs)
// SELECT * FROM user
var mapOfStructs = make(map[int64]Struct)
err := engine.Find(&mapOfStructs)
// SELECT * FROM user
var int64s []int64
err := engine.Table("user").Cols("id").Find(&int64s)
// SELECT id FROM user
4. Query multiple records and record by record handle, there two methods, one is Iterate,
another is Rows
err := engine.Iterate(...)
// SELECT * FROM user
rows, err := engine.Rows(...)
// SELECT * FROM user
defer rows.Close()
bean := new(Struct)
for rows.Next() {
err = rows.Scan(bean)
}
5. Update one or more records
affected, err := engine.ID(...).Update(&user)
// UPDATE user SET ...
6. Delete one or more records, Delete MUST has condition
affected, err := engine.Where(...).Delete(&user)
// DELETE FROM user Where ...
7. Count records
counts, err := engine.Count(&user)
// SELECT count(*) AS total FROM user
counts, err := engine.SQL("select count(*) FROM user").Count()
// select count(*) FROM user
8. Sum records
sumFloat64, err := engine.Sum(&user, "id")
// SELECT sum(id) from user
sumFloat64s, err := engine.Sums(&user, "id1", "id2")
// SELECT sum(id1), sum(id2) from user
sumInt64s, err := engine.SumsInt(&user, "id1", "id2")
// SELECT sum(id1), sum(id2) from user
Conditions
The above 8 methods could use with condition methods chainable.
Attention: the above 8 methods should be the last chainable method.
1. ID, In
engine.ID(1).Get(&user) // for single primary key
// SELECT * FROM user WHERE id = 1
engine.ID(core.PK{1, 2}).Get(&user) // for composite primary keys
// SELECT * FROM user WHERE id1 = 1 AND id2 = 2
engine.In("id", 1, 2, 3).Find(&users)
// SELECT * FROM user WHERE id IN (1, 2, 3)
engine.In("id", []int{1, 2, 3}).Find(&users)
// SELECT * FROM user WHERE id IN (1, 2, 3)
2. Where, And, Or
engine.Where().And().Or().Find()
// SELECT * FROM user WHERE (.. AND ..) OR ...
3. OrderBy, Asc, Desc
engine.Asc().Desc().Find()
// SELECT * FROM user ORDER BY .. ASC, .. DESC
engine.OrderBy().Find()
// SELECT * FROM user ORDER BY ..
4. Limit, Top
engine.Limit().Find()
// SELECT * FROM user LIMIT .. OFFSET ..
engine.Top(5).Find()
// SELECT TOP 5 * FROM user // for mssql
// SELECT * FROM user LIMIT .. OFFSET 0 //for other databases
5. SQL, let you custom SQL
var users []User
engine.SQL("select * from user").Find(&users)
6. Cols, Omit, Distinct
var users []*User
engine.Cols("col1, col2").Find(&users)
// SELECT col1, col2 FROM user
engine.Cols("col1", "col2").Where().Update(user)
// UPDATE user set col1 = ?, col2 = ? Where ...
engine.Omit("col1").Find(&users)
// SELECT col2, col3 FROM user
engine.Omit("col1").Insert(&user)
// INSERT INTO table (non-col1) VALUES ()
engine.Distinct("col1").Find(&users)
// SELECT DISTINCT col1 FROM user
7. Join, GroupBy, Having
engine.GroupBy("name").Having("name='xlw'").Find(&users)
//SELECT * FROM user GROUP BY name HAVING name='xlw'
engine.Join("LEFT", "userdetail", "user.id=userdetail.id").Find(&users)
//SELECT * FROM user LEFT JOIN userdetail ON user.id=userdetail.id
More usage, please visit http://xorm.io/docs
*/
package xorm