sqlsrv_prepare

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sqlsrv_prepare — Prepares a query for execution

说明

sqlsrv_prepare(
    resource $conn,
    string $sql,
    array $params = ?,
    array $options = ?
): mixed

Prepares a query for execution. This function is ideal for preparing a query that will be executed multiple times with different parameter values.

参数

conn

A connection resource returned by sqlsrv_connect().

sql

The string that defines the query to be prepared and executed.

params

An array specifying parameter information when executing a parameterized query. Array elements can be any of the following:

A literal value
A PHP variable
An array with this structure: array($value [, $direction [, $phpType [, $sqlType]]])

The following table describes the elements in the array structure above:

**Array structure**
Element	Description
$value	A literal value, a PHP variable, or a PHP by-reference variable.
$direction (optional)	One of the following SQLSRV constants used to indicate the parameter direction: SQLSRV_PARAM_IN, SQLSRV_PARAM_OUT, SQLSRV_PARAM_INOUT. The default value is SQLSRV_PARAM_IN.
$phpType (optional)	A SQLSRV_PHPTYPE_* constant that specifies PHP data type of the returned value.
$sqlType (optional)	A SQLSRV_SQLTYPE_* constant that specifies the SQL Server data type of the input value.

options

An array specifying query property options. The supported keys are described in the following table:

**Query Options**
Key	Values	Description
QueryTimeout	A positive integer value.	Sets the query timeout in seconds. By default, the driver will wait indefinitely for results.
SendStreamParamsAtExec	`true` or `false` (the default is `true`)	Configures the driver to send all stream data at execution (`true`), or to send stream data in chunks (`false`). By default, the value is set to `true`. For more information, see sqlsrv_send_stream_data().
Scrollable	SQLSRV_CURSOR_FORWARD, SQLSRV_CURSOR_STATIC, SQLSRV_CURSOR_DYNAMIC, or SQLSRV_CURSOR_KEYSET	See » Specifying a Cursor Type and Selecting Rows in the Microsoft SQLSRV documentation.

返回值

Returns a statement resource on success and false if an error occurred.

示例

示例 #1 sqlsrv_prepare() example

This example demonstrates how to prepare a statement with sqlsrv_prepare() and re-execute it multiple times (with different parameter values) using sqlsrv_execute().

<?php
$serverName = "serverName\sqlexpress";
$connectionInfo = array( "Database"=>"dbName", "UID"=>"username", "PWD"=>"password");
$conn = sqlsrv_connect( $serverName, $connectionInfo);
if( $conn === false) {
    die( print_r( sqlsrv_errors(), true));
}

$sql = "UPDATE Table_1
        SET OrderQty = ?
        WHERE SalesOrderID = ?";

// Initialize parameters and prepare the statement. 
// Variables $qty and $id are bound to the statement, $stmt.
$qty = 0; $id = 0;
$stmt = sqlsrv_prepare( $conn, $sql, array( &$qty, &$id));
if( !$stmt ) {
    die( print_r( sqlsrv_errors(), true));
}

// Set up the SalesOrderDetailID and OrderQty information. 
// This array maps the order ID to order quantity in key=>value pairs.
$orders = array( 1=>10, 2=>20, 3=>30);

// Execute the statement for each order.
foreach( $orders as $id => $qty) {
    // Because $id and $qty are bound to $stmt1, their updated
    // values are used with each execution of the statement. 
    if( sqlsrv_execute( $stmt ) === false ) {
          die( print_r( sqlsrv_errors(), true));
    }
}
?>

注释

When you prepare a statement that uses variables as parameters, the variables are bound to the statement. This means that if you update the values of the variables, the next time you execute the statement it will run with updated parameter values. For statements that you plan to execute only once, use sqlsrv_query().

参见

sqlsrv_execute() - Executes a statement prepared with sqlsrv_prepare
sqlsrv_query() - Prepares and executes a query

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＋添加备注

用户贡献的备注 2 notes

down

tuxedobob ¶

9 years ago

Be careful with your variables once you bind them to a statement with sqlsrv_prepare.

Consider the following:

<?php
$dude = '';
$time = new DateTime();
$sql = "INSERT INTO my_table (person, timein) VALUES (?, ?)";
$stmt = sqlsrv_prepare($conn, $sql, array(&$dude, &$time));

...
// many lines later

foreach ($times as &$time) {
   //do stuff
}

// later still...
$time = $times['start'];
if( sqlsrv_execute( $stmt ) === false ) {
          die( print_r( sqlsrv_errors(), true));
}
?>

I did something like this. I prepared a statement at the start, used the variable again in the middle, and then set the value I wanted before running the query.

Trouble is, I used the variable as an iterator instead of a simple scalar. This caused PHP to use a different location in memory, and the location it was previously bound to was invalid. So SQL simply inserted a default date/time.

Worse, because SQL just inserted a default, it didn't throw any errors, and in trying to debug it, I did something like this:

<?php
var_dump($time);
sqlsrv_execute($stmt);
$q = "SELECT * FROM my_table WHERE id=@@IDENTITY";
$r = sqlsrv_query($conn, $q);
$row = sqlsrv_fetch_array($r); $id = $row[0];
var_dump($row['time']);
?>

Having it appear as though you're sending SQL the correct data, and seeing it spitting back something else entirely is absolutely maddening.

So if SQL seems to be inserting garbage with prepared statements, MAKE SURE YOU'RE NOT USING THE VARIABLES ANYWHERE ELSE.

down

-2

matt at bigbadweb dot co dot uk ¶

10 years ago

Example of how to formally specify the params, AND get output.
<?php

// Setup connection
$serverName = "serverName\sqlexpress";
$connectionInfo = array( "Database"=>"dbName", "UID"=>"username", "PWD"=>"password");
$conn = sqlsrv_connect( $serverName, $connectionInfo);
if( $conn === false) {
  die( print_r( sqlsrv_errors(), true));
}

// specify params - MUST be a variable that can be passed by reference!
$myparams['Item_ID'] = intval(-2);
$myparams['Item_Name'] = "Foo";

// Set up the proc params array - be sure to pass the param by reference
$procedure_params = array(
 array(&$myparams['Item_ID'], SQLSRV_PARAM_OUT),
 array(&$myparams['Item_Name'], SQLSRV_PARAM_OUT)
);

// EXEC the procedure, {call stp_Create_Item (@Item_ID = ?, @Item_Name = ?)} seems to fail with various errors in my experiments
$sql = "EXEC stp_Create_Item @Item_ID = ?, @Item_Name = ?";

$stmt = sqlsrv_prepare($conn, $sql, $procedure_params);

if( !$stmt ) {
 die( print_r( sqlsrv_errors(), true));
}

if(sqlsrv_execute($stmt)){
  while($res = sqlsrv_next_result($stmt)){
    // make sure all result sets are stepped through, since the output params may not be set until this happens
  }
  // Output params are now set,
  print_r($params);
  print_r($myparams);
}else{
  die( print_r( sqlsrv_errors(), true));
}
?>