MySQL and mSQL

Data Processing

Part I, introduced the concepts of transaction management and result sets. A database application is nothing more than a tool for managing database transactions and processing result sets. For example, if you have an address book application, your processing of result sets is the grabbing of each row from the database and displaying it for the user. Your transaction management simply amounts to making sure that an update to the address and person tables are handled as a single unit.

Note

As we have mentioned before, MySQL and mSQL have no support for transaction management. Any modification you make to the database is automatically committed when you send it. This limitation requires you to go to special lengths to make sure you do not end up with corrupt data from transactions that fail in the middle of two related accesses.

The other two important pieces to database application flow are connection and disconnection. It stands to reason that before you actually issue a query, you should first connect to the database. It is not uncommon, however, for people to forget the other piece of the puzzle—cleaning up after themselves. You should always free up any database resources you grab the minute you are done with them. In a long-running application like an Internet daemon process, a badly written system can eat up database resources until it locks up the system.

Part of cleaning up after yourself involves proper error handling. Better programming languages make it harder ...