How Can I Safely Escape Strings in SQL Server Queries Using PHP?

Escaping Strings in SQL Server Using PHP: A Comprehensive Guide

When working with SQL Server using PHP, it's crucial to protect your data from SQL injection attacks by properly escaping strings. This is a technique to prevent malicious input from being interpreted as SQL commands.

Alternative to mysql_real_escape_string()

Unlike MySQL, SQL Server does not provide a built-in function equivalent to mysql_real_escape_string().

Enter addslashes()

addslashes() is a PHP function that is often considered as a potential alternative for string escaping. However, it's important to note that addslashes() is not fully adequate for use with SQL Server databases.

A More Robust Solution

The ideal solution is to manually encode the data as a hex bytestring. Here's a code snippet to guide you:

$unpacked = unpack('H*hex', $data);
mssql_query('
    INSERT INTO sometable (somecolumn)
    VALUES (0x' . $unpacked['hex'] . ')
');

Abstraction for Reusable Escaping

To simplify and reuse the escaping process, you can create a custom function like this:

function mssql_escape($data) {
    if(is_numeric($data))
        return $data;
    $unpacked = unpack('H*hex', $data);
    return '0x' . $unpacked['hex'];
}

mssql_query('
    INSERT INTO sometable (somecolumn)
    VALUES (' . mssql_escape($somevalue) . ')
');

Alternative to mysql_error()

For error handling, SQL Server provides mssql_get_last_message() as an alternative to mysql_error().

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