Thinkphp6 framework for learning: basic operations on databases

This article will mention:

1. native query operation reads: query ()

2. native query operation writes: insert / update / delete, execute ()

3. Query Builder

4.where () function: can query based on other fields

5.order (), limit () function

 

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For the configuration database in the frame app \ config \ database.php has been configured, it will default to the following has been connected to the database

As a data table example shows:

 

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1. native query operation reads: query ()

public function demo1()
    {
        $sql = "SELECT `userName` FROM `admin` WHERE `id`=:id ";
        $map = ['id' => 1];
        $res = Db::query($sql, $map);
        dump($res);//打印查询结果$res
    }

 

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2. native query operation writes: insert / update / delete, execute ()

public  function demo2 () 
    { 
        $ SQL = "status` the UPDATE =` `admin` the SET: the WHERE Status =` id`: ID " ;
         $ Map = [ 'ID' =>. 1, 'Status' => 0 ];
         $ RES = Db :: Execute ( $ SQL , $ Map );
         return 'successfully updated'. $ RES 'record'. ; 
    }

Data table id = status 1 from 1 to 0

 

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3. Query Builder

① find (): returns the first record satisfying the condition, a single record; no return null

// Table (): Set the data table 
    // field (): set the query field list 
    public  function Demo3 () 
    { 
        $ RES = Db :: Table ( 'ADMIN' )
             -> Field ( 'ID, the userName, Phone' )
             - > Find (2); // supports the primary key as a parameter: the WHERE `2 = id` 
        the dump ( $ RES ); 
    }

 

②select (): returns multiple records satisfy the conditions

public  function demo4 () 
    { 
        $ RES = Db :: Table ( 'ADMIN' )
             -> Field ( 'ID, the userName, Phone' )
             // NOTE: select (2, 3) returns only the first; select ([2 3]) should be placed in the array 
            -> SELECT (); // above 
        the dump ( $ RES ); 
    }

 

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. 4 where () function: can query based on other fields

Set the search criteria main types: string, expressions, arrays

(1) String

public  function demo5 () 
    { 
        $ RES = Db :: Table ( 'ADMIN' )
             -> Field ( 'ID, the userName, Phone') // Field () returns only the corresponding fields 

            // character string. 
            -> WHERE ( ' Status> 0 ' )
             -> SELECT (); 
        the dump ( $ RES ); 
}

 

(2) Expressions

public  function demo5 () 
    { 
        $ RES = Db :: Table ( 'ADMIN' )
             -> Field ( 'ID, the userName, Phone') // Field () returns only the corresponding fields 

            @ 2 expression: Recommended. 
            -> WHERE ( 'ID', 'BETWEEN', [l, 3]) // parameter format: field, operator, value 
            -> SELECT (); 
        the dump ( $ RES ); 
}

 

(3) an array

① associative array: the equivalent of inquiry, AND

public  function demo5 () 
    { 
        $ RES = Db :: Table ( 'ADMIN' )
             -> Field ( 'ID, the userName, Phone') // Field () returns only the corresponding fields 

           // ① associative array 
            -> where ([ ' ID '=>. 1,' Phone '=> 123 ])
             -> SELECT (); 
        the dump ( $ RES ); 
}

Sql statement print look (in where () and select () is inserted into the intermediate code below)

->fetchSql(true)

② indexed array: batch query

public function demo5()
    {
        $res = Db::table('admin')
            ->field('id, userName, phone')//field()仅返回对应字段

          //②索引数组
            ->where([
                // ‘0=>’ 索引值可以忽略，默认值
                0 => ['id','between',[1,3]],
                1 => ['status','>',0]
            ])

            ->select();
        dump($res);
}

 

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5.order()，limit()函数

①单字段排序

//order()，limit()
    public function demo6()
    {
        $res = Db::table('admin')
            ->field('id, userName, phone')

            //单字段排序
            ->order('id', 'desc')//默认升序asc，desc：降序
            ->limit(2,2)//从第2行开始的2条数据，常用于分页查询

            ->select();
        dump($res);
    }

 

②多字段排序，用数组参数

讲单字段排序中order()一行改为以下代码即可

->order(['id'=>'asc', 'phone'=>'desc'])