(PHP 5)
mysqli_stmt::prepare -- mysqli_stmt_prepare — Prepare an SQL statement for execution
Stile orientato agli oggetti
Stile procedurale
Prepares the SQL query pointed to by the null-terminated string query.
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.
Nota:
In the case where you pass a statement to mysqli_stmt_prepare() that is longer than max_allowed_packet of the server, the returned error codes are different depending on whether you are using MySQL Native Driver (mysqlnd) or MySQL Client Library (libmysql). The behavior is as follows:
mysqlnd on Linux returns an error code of 1153. The error message means "got a packet bigger than max_allowed_packet bytes".
mysqlnd on Windows returns an error code 2006. This error message means "server has gone away".
libmysql on all platforms returns an error code 2006. This error message means "server has gone away".
stmtSolo nello stile procedurale: un identificatore di statement restituito da mysqli_stmt_init().
query
The query, as a string. It must consist of a single SQL statement.
You can include one or more parameter markers in the SQL statement by embedding question mark (?) characters at the appropriate positions.
Nota:
You should not add a terminating semicolon or \g to the statement.
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 Language (DML) statements, and not in Data Definition Language (DDL) statements.
Restituisce TRUE in caso di successo, FALSE in caso di fallimento.
Example #1 Stile orientato agli oggetti
<?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();
?>
Example #2 Stile procedurale
<?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 */
$stmt = mysqli_stmt_init($link);
if (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);
?>
I precedenti esempi visualizzeranno:
Amersfoort is in district Utrecht