mysqli_prepare

Manuale PHP
Indietro		Avanti

Description

Procedure style:

mixed mysqli_prepare ( mysqli link, string query )

Object oriented style (method)

class mysqli {

mixed prepare ( string query )

}

mysqli_prepare() prepares the SQL query pointed to by the null-terminated string query, and returns a statement handle to be used for further operations on the statement. The query must consist of a single SQL statement.

Nota: 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.

Nota: 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.

Valori restituiti

mysqli_prepare() returns a statement object or FALSE if an error occured.

Vedere anche:

mysqli_stmt_execute(), mysqli_stmt_fetch(), mysqli_stmt_bind_param(), mysqli_stmt_bind_result() e mysqli_stmt_close().

Esempi

Esempio 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 */
if ($stmt = $mysqli->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();
?>

Esempio 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 */
if ($stmt = mysqli_prepare($link, "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);
?>

The above example will output:

Amersfoort is in district Utrecht

Indietro	Partenza	Avanti
mysqli_ping	Risali	mysqli_query