debugging

Introduction
Debugging SQL code is a very important task these days. Unfortunately not all database servers support this feature. And MySQL is one of such servers. In spite of its wide feature set, debugging is not implemented in it. So the problem is that MySQL provides no API functionalities for code debugging. But the necessity to debug SQL code does not disappear and becomes more and more important each year. Some companies that develop tools to access data of MySQL server databases create their own debuggers that solve this problem to some extent.

Types of Debuggers
Now we will consider the types of debuggers that can be implemented for MySQL server and principles of their work.
(more…)

Introduction

MySQL Server (starting from v 5.0), as Oracle and SQL Servers, allows creating stored procedures and functions.

Stored procedures are a set of SQL commands that can be compiled and stored on the server. Thus instead of storing a frequently-used query, we can refer to a corresponding stored procedure. This provides better performance (as this query is analyzed only once) and reduction of traffic between client and server.

While developing business logic of procedures, we often use a great number of variables (e.g., temporary outputs) to store. To assign static values to a variable or values of other variables, SET operator is used. SET operator in stored procedures is an extended version of usual SET operator. This allows using extended syntax SET а=х, Ь=у, where different variables types (local and server variables, global and session ones) can be mixed.

Problem

(more…)