thinkphp5.0 study notes database operation

ThinkPHP has a built-in abstract database access layer that encapsulates different database operations. We only need to use the public Db class to operate without writing different codes and underlying implementations for different databases. The Db class will Automatically call the corresponding database driver for processing. Using PDO method, it currently includes support for Mysql, SqlServer, PgSQL, Sqlite and other databases.

1. Basic use

After configuring the database connection information, we can directly use the database to run native SQL operations, supportquery (query operation) and execute (write operation) methods, and support parameter binding.

public function read()
{$sql = Db::query('select * from news');
    dump($sql);   
    
}

The output is:

execute method:

public function read()
{$sql = Db::execute('insert into news (nid, rid) values (11, 11)');;
    dump($sql);
}

Output:

Database added successfully!

also supports named placeholder bindings, for example:

public function read()
{$sql = Db::query('select * from news where nid=:nid',['nid'=>1]);
    dump($sql);
}

Output:

execute method:

public function read()
{$sql = Db::execute('insert into news (nid, rid) values (:nid, :rid)',['nid'=>18,'rid'=>'121']);
    dump($sql);
}

Output :

Database added successfully!

Multiple database connections can be used :

2. Query constructor

You can tell by the name, it’s very pretentious..

Let’s look at the basic query;

Query a data:

 // table方法必须指定完整的数据表名$sql =Db::table('news')->where('nid',1)->find();
    dump($sql);

find = Query one item; and the query result does not exist, return null

Output:

Db::table('think_user')->where('status',1)->select();

This query statement is the same as the above, but the select method query result does not exist and an empty array is returned.

Well, this thing is called a query data set, that’s right!

By default, the find and select methods return arrays.

If you want to query the value of a certain field, what should you do?

public function read()
{// 返回某个字段的值$sql =Db::table('news')->where('nid',18)->value('rid');
    dump($sql);
}

public function read()
{$sql =Db::table('news')->chunk(1,function($user){foreach($user as $u)
        {
dump($u);
        }
    });
    

}

public function read()
{$data = ['ntitle' => '123', 'rid' => '456'];$sql = Db::table('news')->insert($data);
    
dump($sql);
}

public function read()
{$data = ['ntitle' => '123', 'rid' => '345'];$sql = Db::table('news')->insert($data);$userId = Db::name('news')->getLastInsID('nid');
dump($userId);
dump($sql);
}

public function read()
{$data = [
['ntitle' =>'gaga','rid' => '12'],['ntitle' =>'gaaaga','rid' => '123']
];$sql = Db::table('news')->insertAll($data);

dump($sql);
}

public function read()
{//    根据主键 来删$sql = Db::table('news')->delete(1);//多删
//$sql = Db::table('news')->delete(1,2,3);dump($sql);
}

public function read()
{//    根据条件 来删$sql = Db::table('news')->where('nid',18)->delete();//多删
//$sql = Db::table('news')->where('nid','<&#39;,1)->delete();dump($sql);
}

public function read()
{$sql = Db::table('news')->where('nid',20)->where('ntitle',123)->find();
dump($sql);
}

public function read()
{$sql = Db::table('news')->where('nid',20)->whereOr('ntitle','like','%123%')->find();
dump($sql);
}

public function read()
{$sql = Db::table('news')->where(function($query){$query->where('nid',21)->where('nid',22);
})->whereOr(function($query)
{$query->where('ntitle','123')->whereOr('ntitle','123');
})->select();
dump($sql);
}

SELECT * FROM `news` WHERE  (  `nid` = 1 OR `nid` = 2 ) OR (  `ntitle` LIKE '123' OR `ntitle` LIKE '123' )

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