How to: Specify Parameter Direction Using the SQLSRV Driver

Article
11/30/2010

This topic describes how to use the SQLSRV driver to specify parameter direction when you call a stored procedure. Note that the parameter direction is specified when you construct a parameter array (step 3) that is passed to sqlsrv_query or sqlsrv_prepare.

To specify parameter direction

Define a Transact-SQL query that calls a stored procedure. Use question marks (?) instead of the parameters to be passed to the stored procedure. For example, this string calls a stored procedure (UpdateVacationHours) that accepts two parameters:
```
$tsql = "{call UpdateVacationHours(?, ?)}";
```
Note

Calling stored procedures using canonical syntax is the recommended practice. For more information about canonical syntax, see Calling a Stored Procedure.
Initialize or update PHP variables that correspond to the placeholders in the Transact-SQL query. For example, the following code initializes the two parameters for the UpdateVacationHours stored procedure:
```
$employeeId = 101;
$usedVacationHours = 8;
```
Note

Variables that are initialized or updated to null, DateTime, or stream types cannot be used as output parameters.
Use your PHP variables from step 2 to create or update an array of parameter values that correspond, in order, to the parameter placeholders in the Transact-SQL string. Specify the direction for each parameter in the array. The direction of each parameter is determined in one of two ways: by default (for input parameters) or by using SQLSRV_PARAM_* constants (for output and bidirectional parameters). For example, the following code specifies the $employeeId parameter as an input parameter and the $usedVacationHours parameter as a bidirectional parameter:
```
$params = array(
                 array($employeeId, SQLSRV_PARAM_IN),
                 array($usedVacationHours, SQLSRV_PARAM_INOUT)
                );
```
To understand the syntax for specifying parameter direction in general, suppose that $var1, $var2, and $var3 correspond to input, output, and bidirectional parameters, respectively. You can specify the parameter direction in either of the following ways:
- Implicitly specificy the input parameter, explicitly specify the output parameter, and explicitly specify a bidirectional parameter:
```
array( 
       array($var1),
       array($var2, SQLSRV_PARAM_OUT),
       array($var3, SQLSRV_PARAM_INOUT)
       );
```
- Explicitly specificy the input parameter, explicitly specificy the output parameter, and explicitly specificy a bidirectional parameter:
```
array( 
       array($var1, SQLSRV_PARAM_IN),
       array($var2, SQLSRV_PARAM_OUT),
       array($var3, SQLSRV_PARAM_INOUT)
       );
```
Execute the query with sqlsrv_query or with sqlsrv_prepare and sqlsrv_execute. For example, the following code uses the connection $conn to execute the query $tsql with parameter values specified in $params:
```
sqlsrv_query($conn, $tsql, $params);
```

How to: Specify Parameter Direction Using the SQLSRV Driver

To specify parameter direction

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