Professional SQL Server™ 2005 Programming

10.6. Summary

Understanding scripts and batches is the cornerstone to an understanding of programming withSQL Server. The concepts of scripts and batches lay the foundation for a variety of functions fromscripting complete database builds to programming stored procedures and triggers.

Local variables have scope for only one batch. Even if you have declared the variable withinthe same overall script, you will still get an error message if you don't re-declare it (and startover with assigning values) before referencing it in a new batch.

There are over 30 system functions. We provided a listing of some of the most useful system functions, but there are many more. Try checking out the Books Online or Appendix A at the back ofthis book for some of the more obscure ones. System functions do not need to be declared, and are always available. Some are scoped to the entire server, while others return values specific to thecurrent connection.

You can use batches to create precedence between different parts of your scripts. The first batch starts at the beginning of the script and ends at the end of the script or the first GO statement — whichever comes first. The next batch (if there is another) starts on the line afterthe first one ends and continues to the end of the script or the next GO statement — again, whichever comesfirst. The process continues to the end of the script. The first batch from the topof the script is executed first, the second is executed second, and so on. All commands ...