// Copyright 2013 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

	go get github.com/lunny/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 is enough. You can set it as package variable.

Usage

Xorm also support raw sql execution:

1. query sql, the returned results is []map[string][]byte

	results, err := engine.Query("select * from user")

2. exec sql, the returned results

	affected, err := engine.Exec("update user set .... where ...")

There are 7 major ORM methods and many helpful methods to use to operate database.

1. Insert one or multipe 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 from database

	has, err := engine.Get(&user)
	// SELECT * FROM user LIMIT 1

3. Query multiple records from database

	err := engine.Find(...)
	// SELECT * FROM user

4. Query multiple records and record by record handle

	err := engine.Iterate(...)
	// SELECT * FROM user

5. Update one or more records

	affected, err := engine.Update(&user)
	// UPDATE user SET

6. Delete one or more records

	affected, err := engine.Delete(&user)
	// DELETE FROM user Where ...

7. Count records

	counts, err := engine.Count(&user)
	// SELECT count(*) AS total FROM user

Condition

The above 7 methods could use with condition methods.

1. Id, In

	engine.Id(1).Get(&user)
	// SELECT * FROM user WHERE id = 1

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().Find()
	// SELECT * FROM user LIMIT ..

5. Sql

	engine.Sql("select * from user").Find()

6. Cols, Omit, Distinct

	engine.Cols("col1, col2").Find()
	// SELECT col1, col2 FROM user
	engine.Omit("col1").Find()
	// SELECT col2, col3 FROM user
	engine.Distinct("col1").Find()
	// SELECT DISTINCT col1 FROM user

7. Join, GroupBy, Having

	engine.GroupBy("name").Having("name='xlw'").Find()
	//SELECT * FROM user GROUP BY name HAVING name='xlw'
	engine.Join("LEFT", "userdetail", "user.id=userdetail.id").Find()
	//SELECT * FROM user LEFT JOIN userdetail ON user.id=userdetail.id

*/
package xorm