PHP mysql\mysqli\pdo (ii) mysqli

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Mysqli has an object-oriented style and a process-oriented style, a personal feeling or an object-oriented style is better (after all, object-oriented)

1, Mysqli::_construct ()

mysqli::__construct  ([ string  $host  = ini_get (" Mysqli.default_host ")  [, string  $username  = ini_get (" Mysqli.default_user ")  [,  string  $passwd  = ini_get ("MYSQLI.DEFAULT_PW")  [, string$dbname =  ""  [, int  $port  = ini_get ("Mysqli.default_port")  [, string  $socket   = ini_get ("Mysqli.default_socket")  ]]]]]] ) mysqli mysqli_connect  ([ string  $host  = ini_get ("Mysqli.default_host")  [, string  $username = ini_get (" Mysqli.default_user ")  [, string  $passwd  = ini_get (" MYSQLI.DEFAULT_PW ")  [,string   $dbname  =  " [, int  $port  = ini_get (" Mysqli.default_port ")  [,  string  $socket  = ini_get ("Mysqli.default_socket")  ]]]]]] ) 

$host, $username, $passwd, $dbname, $port Needless to say, the rules are similar to MySQL.

2, Mysqli::close ()

Object-oriented style bool Mysqli::close (void)//Process style bool Mysqli_close (mysqli $link) returns TRUE on success, or FALSE on failure. $link: The link identity returned by Mysqli_connect () or mysqli_init (void), which provides a Mysqli object for use by Mysqli_options () and Mysqli_real_connect ().

The difference between this and mysql_close () is that mysql_close () can close the previous connection without providing parameters.

3, Mysqli::query ()

Mixed Mysqli::query (string $query [, int $resultmode = Mysqli_store_result]) mixed mysqli_query (mysqli $link, string $query [, int $resultmode = Mysqli_store_result])

$resultmode There are two ways to take a value:MYSQLI_USE_RESULTAndMYSQLI_STORE_RESULT(默认值)，区别在于MYSQLI_USE_RESULT模式下取结果时每次都要从服务器上取结果而MYSQLI_STORE_RESULT则是将结果一步到位缓存到用户程序空间中。所以当查询结果数据量特别大时用MYSQLI_USE_RESULT，MYSQLI_STORE_RESUL则速度非常快。

return value:Return on FailureFALSEPassMysqli_query ()Successful executionSELECT, SHOW, DESCRIBEOrEXPLAINThe query returns a Mysqli_result object, other queries return true

4. Traverse the result function

Object-oriented style mixed mysqli_result::fetch_array ([int $resulttype = Mysqli_both])//process-oriented mixed Mysqli_fetch_array (mysqli_r Esult $result [, int $resulttype = Mysqli_both])

Cases:

 $query  =  "select name, countrycode from  City order by id limit 3 "; $result  =  $mysqli->query ($query);/*  numeric array */$row  =  $result->fetch_array (mysqli_num);p rintf  ("%s  (%s) \ n",   $row [0],  $row [1]);/* associative array */$row  =  $result->fetch_array ( MYSQLI_ASSOC);p rintf  ("%s  (%s) \ n",  $row ["Name"],  $row ["CountryCode"]);/* associative  and numeric array */$row  =  $result->fetch_array (mysqli_both);p rintf  ("% s  (%s) \ n ",  $row [0],  $row [" CountryCode "]); 

Similar functions are: Mysqli_result::fetch_assoc and Mysqli_result::fetch_row, Mysqli_result::fetch_object.

5. Release the result function

Object-oriented style void Mysqli_result::free (void) OID mysqli_result::close (void) void Mysqli_result::free_result (void)//process-oriented style void Mysqli_free_result (Mysqli_result $result)

6. Other functions

Mysqli::real_escape_string (string $sql) escapes SQL.

Executing multiple SQL at a time can use the Multi_query () method of the Mysqli object:

BOOL Mysqli::multi_query (String $query)

When passing parameters, multiple SQL commands need to be written in the same string as arguments to Multi_query (), and multiple SQL uses semicolons (;) delimited. If the first SQL command executes without error, this method returns True, otherwise false is returned.

Because each SQL in the Multi_query parameter may return a result, the process becomes:

if  ($mysqli->multi_query ($sql))  {    do {         if  ($result  =  $mysqli->store_result ())  {             while  ($row  =  $result->fetch_row ())  {                 foreach  ( $row  as  $data)  {                     var_dump ($data);                 }             }             $result->close ();         }        if  ($ Mysqli->more_results ())  {            echo  '----------------';         }    } while ($mysqli->next_result ());}

PHP mysql\mysqli\pdo (ii) mysqli