Summary of yii database query operations_PHP tutorial

Yii database query operation summary

A summary of database query data methods under the yii framework.

(1)$result=Yii::app()->dbName->createCommand($sql)->queryRow();

The returned result set is a one-dimensional array if it is not empty. The dbName in the code is the name of the library where the data table is located, and $sql can be any SQL statement.

(2)$result=Yii::app()->dbName->createCommand($sql)->queryAll();

The returned result set is a two-dimensional array if it is not empty. The dbName in the code is the name of the library where the data table is located, and $sql can be any SQL statement.

(3)$result=Region::model()->findByPk($id);

The returned result is an object if it is not empty. Region in the code represents the Region.php file stored in the models directory. The value of $id here represents the value equal to the primary key defined in Region.php.

(4)$result=Region::model()->findAll($condition,$params);

For example: findAll("username=:name",array(":name"=>$username));

If the result set returned is not empty, it is a two-dimensional array, and the first dimension of the result set of the array is an object.

(5)$admin=User::model()->findAllByPk($postIDs,$condition,$params);

For example: findAllByPk($id,"name like ':name' and age=:age",array(':name'=>$name,'age'=>$age));

This method queries a set based on the primary key. If the returned result set is not empty, it will be a two-dimensional array. The first dimension of the result set of the array is an object. You can also use multiple primary keys, such as: findAllByPk(array(1,2));

(6)$admin=User::model()->findAllBySql($sql,$params);

If the returned result set is not empty, it will be a two-dimensional array. The first dimension of the result set of the array is an object. Examples of use are:

findAllBySql("select * from admin where username=:name",array(':name'=>'admin'));

(7)$post=Post::model()->findBySql($sql,$params);

The returned result set is an object if it is not empty, and the query result is only the first piece of data. Such as:

findBySql("select * from user where username=:name",array(':name'=>'phpernote.com'));

(8)$row=User::model()->find($condition,$params);

The returned result set is an object if it is not empty, and the query result is only the first piece of data. Such as:

find('username=:name',array(':name'=>'admin'));

or:

find(array('condition'=>'user_id=:user_id','params'=>array(':user_id'=>$uid)));

(9)$admin=User::model()->findByAttributes($attributes,$condition,$params);

This method is to query data based on conditions, which can be multiple conditions. Put the conditions into an array. The query result set is an object and has only one piece of data, such as:

findByAttributes(array('username'=>'admin'));

or:

(10)$admin=User::model()->findAllByAttributes($attributes,$condition,$params);

The returned result set is a two-dimensional array if it is not empty, and the result set in the first dimension of the array is an object.

(9)

// If the query conditions are very complex, use the CDbCriteria class

$criteria=new CDbCriteria;
$criteria->select='title';
$creteria->condition='postID=:postID';
$criteria->params=array(':postID'=>10);
$post=Post::model()->find($criteria); // No second parameter required

//Another better way of writing

$post=Post::model()->find(
array(
         'select'=>'title',
         'condition'=>'postID=:postID',
          'params'=>array(':postID'=>10)
)
);

Query the number and determine whether the query has results

1. $n=Post::model()->count($condition,$params);

This method is to query how many records a collection has based on a condition and return an int number, such as:

count("username=:name",array(":name"=>$username)); 

2. $n=Post::model()->countBySql($sql,$params);

This method is to query how many records a collection has according to the SQL statement and return an int type number, such as:

countBySql("select * from admin where username=:name",array(':name'=>'admin'));

3. $exists=Post::model()->exists($condition,$params);

This method is to query whether the array obtained has data based on a condition. If there is data, it returns true, otherwise it is not found.

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