Summary

This hour discussed extensions to standard SQL among vendors' implementations and their compliance with the ANSI standard. Once you learn SQL, you can easily apply your knowledge—and your code—to other implementations of SQL. SQL is portable between vendors, being that most SQL code can be utilized among most implementations with a few minor modifications.

The last part of this hour was spent showing two specific extensions used by three implementations. Transact-SQL is used by Microsoft SQL Server and Sybase, and PL/SQL is used by Oracle. You should have seen some similarities between Transact-SQL and PL/SQL. One thing to note is that these two implementations have first sought their compliance with the standard, and then added enhancements to their implementations for better overall functionality and efficiency. Also discussed was MySQL, which was designed to increase performance for large database queries. This hour intended to make you aware that many SQL extensions do exist and to teach the importance of a vendor's compliance to the ANSI SQL standard.

If you take what you have learned in this book and apply it (build your code, test it, and build upon your knowledge), you are well on your way to mastering SQL. Companies have data and cannot function without databases. Relational databases are everywhere—and because SQL is the standard language with which to communicate and administer a relational database, you have made an excellent decision by learning SQL. Good luck!