MySQL Stored Procedure Programming

Handling Stored Program Errors in the Calling Application

Throughout this chapter, we’ve often talked about “returning the error to the calling application.” In our examples we have used the MySQL command-line client to represent the calling application since this client is common to all environments and readers, and it allows you (and us) to quickly test out the stored program.

In production environments, however, the calling application will not be the MySQL command-line program, but possibly a web-based application using PHP , Perl, Java, Python, or .NET (C# or Visual Basic) to interface with the MySQL stored program. In Chapters 12 through 17, we look in detail at how to invoke stored programs from a variety of languages. We also cover various techniques for retrieving status and error messages from these languages. However, since we’re on the topic of error handling , let’s briefly look at how we can process errors generated by a stored program called from each of these languages.

PHP

PHP provides a variety of ways of interacting with MySQL. There are four major interfaces available:

PEAR (PHP Extension and Application Repository)

The PEAR repository includes a standard, database-independent module called PEAR DB that can be used to interface with almost any relational database.

mysql

PHP includes a MySQL-specific interface inventively called the mysql extension.

mysqli

Commencing with PHP 5, a new interface—mysqli—was introduced (according to the developer, the "i" stands for “any ...