Yii uses DAO to operate databases

Yii uses DAO to operate databases

DAO obtains a record:

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$ SQL = "select title, id from {blog} where id =: id"; $ command = Yii: app () -> db-> createCommand ($ SQL); $ id = (int) $ _ GET ['id']; $ command-> bindParam (": id", $ id, PDO: PARAM_INT); $ data = $ command-> queryRow (); // The bindParam () method is very similar to bindValue. The only difference is that the former uses a PHP variable to bind a parameter, while the latter uses a value. For the big data block parameters in the memory, the performance should be considered first.

Obtain multiple records:

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123	$ SQL = "select title, id from {blog}"; $ command = Yii: app ()-> db-> createCommand ($ SQL ); $ data = $ command-> queryAll ();

Obtain a field of a record:

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12345

$ SQL = "select title from {blog} where id =: id"; $ command = Yii: app ()-> db-> createCommand ($ SQL ); $ id = (int) $ _ GET ['id']; $ command-> bindParam (": id", $ id, PDO: PARAM_INT ); $ title = $ command-> queryScalar ();

Use transactions:

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$ Transaction = Yii: app ()-> db-> beginTransaction (); try {$ SQL = "update {blog} set title = 'abc' where id = 2"; Yii: app ()-> db-> createCommand ($ SQL) -> execute (); $ transaction-> commit ();} catch (Exception $ e) {$ transaction-> rollback ();}

Insert data:

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123456789

$ SQL = "insert into {blog} (title) values (: title)"; $ command = Yii: app () -> db-> createCommand ($ SQL); $ title = 'abc'; $ command-> bindParam (": title", $ title, PDO: PARAM_STR ); $ command-> execute (); $ title = 'bbbbbb'; $ command-> bindParam (": title", $ title, PDO: PARAM_STR ); $ command-> execute ();