mysqli::stmt_init()

(PHP 5, PHP 7)

初始化一条语句并返回一个用于mysqli_stmt_prepare(调用)的对象

说明

面向对象风格
mysqli::stmt_init(void): mysqli_stmt

过程化风格
mysqli_stmt_init(mysqli$link): mysqli_stmt

分配并初始化一个语句对象用于mysqli_stmt_prepare().

Note:

任何其后调用的mysqli_stmt函数都会失败直到mysqli_stmt_prepare()被调用.

参数

$link

仅以过程化样式：由mysqli_connect()或mysqli_init()返回的链接标识。

返回值

Returns an object.

参见

• mysqli_stmt_prepare() Prepare an SQL statement for execution

stmt_init() seems to clear previous (possibly erroneous) results on the DB connection, which means you don't necessarily need to use it but it could make the code more robust.
In a PHPUnit test, I had a sequence of prepared queries on the same connection. One of them fetched a row from a SELECT but didn't keep fetching until it drained the connection, so it left some stale results. When the next query did this:
<?php
$db = $this->getConnection() >getDbConnection();
$preparedQuery = $db->prepare ($query);
?>
the prepare() call generated an error: "Could not prepare query: Commands out of sync; you can't run this command now." Changing to this:
<?php
$db = $this->getConnection() >getDbConnection();
$preparedQuery = $db->stmt_init();
$preparedQuery->prepare ($query);
?>
resolved the problem.

you can use $stmt = $mysqli->prepare(); directly without stmt-init() . i think there is no need for stmt-init .

If your sql query has some errors and you don't use stmt_init() before preparing the statement, you won't get error message for wrong sql query.