mysqli_stmt_prepare

(PHP 5)

mysqli_stmt_prepare

(no version information, might be only in CVS)

stmt->prepare --  Prepare a SQL statement for execution

Description

Procedure style:

bool mysqli_stmt_prepare ( mysqli_stmt stmt, string query )

Object oriented style (method)

class mysqli_stmt {

mixed prepare ( string query )

}

mysqli_stmt_prepare() prepares the SQL query pointed to by the null-terminated string query. The statement object has to be allocated by mysqli_stmt_init(). The query must consist of a single SQL statement.

Замечание: You should not add a terminating semicolon or \g to the statement.

The parameter query can include one or more parameter markers in the SQL statement by embedding question mark (?) characters at the appropriate positions.

Замечание: The markers are legal only in certain places in SQL statements. For example, they are allowed in the VALUES() list of an INSERT statement (to specify column values for a row), or in a comparison with a column in a WHERE clause to specify a comparison value.

However, they are not allowed for identifiers (such as table or column names), in the select list that names the columns to be returned by a SELECT statement), or to specify both operands of a binary operator such as the = equal sign. The latter restriction is necessary because it would be impossible to determine the parameter type. In general, parameters are legal only in Data Manipulation Languange (DML) statements, and not in Data Defination Language (DDL) statements.

The parameter markers must be bound to application variables using mysqli_stmt_bind_param() and/or mysqli_stmt_bind_result() before executing the statement or fetching rows.

Возвращаемые значения

Возвращает TRUE в случае успешного завершения или FALSE в случае возникновения ошибки.

Смотрите также

mysqli_stmt_init(), mysqli_stmt_execute(), mysqli_stmt_fetch(), mysqli_stmt_bind_param(), mysqli_stmt_bind_result() и mysqli_stmt_close().

Примеры

Пример 1. Object oriented style

<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
   printf("Connect failed: %s\n", mysqli_connect_error());
   exit();
}

$city = "Amersfoort";

/* create a prepared statement */
$stmt =  $mysqli->stmt_init();
if ($stmt->prepare("SELECT District FROM City WHERE Name=?")) {

   /* bind parameters for markers */
   $stmt->bind_param("s", $city);

   /* execute query */
   $stmt->execute();

   /* bind result variables */
   $stmt->bind_result($district);

   /* fetch value */
   $stmt->fetch();

   printf("%s is in district %s\n", $city, $district);

   /* close statement */
   $stmt->close();
}

/* close connection */
$mysqli->close();
?>

Пример 2. Procedural style

<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
   printf("Connect failed: %s\n", mysqli_connect_error());
   exit();
}

$city = "Amersfoort";

/* create a prepared statement */
$stmt = mysqli_stmt_init();
if ($stmt = mysqli_stmt_prepare($stmt, "SELECT District FROM City WHERE Name=?")) {

   /* bind parameters for markers */
   mysqli_stmt_bind_param($stmt, "s", $city);

   /* execute query */
   mysqli_stmt_execute($stmt);

   /* bind result variables */
   mysqli_stmt_bind_result($stmt, $district);

   /* fetch value */
   mysqli_stmt_fetch($stmt);

   printf("%s is in district %s\n", $city, $district);

   /* close statement */
   mysqli_stmt_close($stmt);
}

/* close connection */
mysqli_close($link);
?>

Результат выполнения данного примера:

Amersfoort is in district Utrecht


mysqli_stmt_prepare
andrey at php dot net
07-Oct-2005 05:35
If you select LOBs use the following order of execution or you risk mysqli allocating more memory that actually used

1)prepare()
2)execute()
3)store_result()
4)bind_result()

If you skip 3) or exchange 3) and 4) then mysqli will allocate memory for the maximal length of the column which is 255 for tinyblob, 64k for blob(still ok), 16MByte for MEDIUMBLOB - quite a lot and 4G for LONGBLOB (good if you have so much memory). Queries which use this order a bit slower when there is a LOB but this is the price of not having memory exhaustion in seconds.
programmer at bardware dot de
10-Dec-2004 03:56
Hi,

the code
($stmt = mysqli_stmt_prepare($stmt, "SELECT District FROM City WHERE Name=?")) {

in the sample is wrong.

mysqli_stmt_prepare returns a bool
When using the code provided $stmt after the call to mysqli_stmt_prepare is a bool a not a mysqli-Statement any longer....may thus not be used in subsequent mysqli_* calls.

Best wishes
Bernhard

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 Last updated: Tue, 15 Nov 2005