Database Wisdom: SQL - DDL

DDL

DDL, Data Definition Language, is concerned with creating, modifying and removing database objects. Creating tables and indexes, adding or removing columns from tables, creating or removing synonyms, creating storage areas to store data, etc. Even renaming a database object is considered DDL.

So, DML is concerned with managing data and DDL is concerned with managing database objects. A solid understanding of SQL requires a solid understanding of both DML and DDL. However, not every user of SQL really requires a knowledge of DDL.

DDL is a design time language. You create the database once, you create your tables and then use them. Your applications will constantly use DML but DDL should, in general, be complete before the developers or users begin using the database.

For this reason, I have split DML and DDL into two books. I will not cover any DDL commands or other design time issues. This book is for people ready to start writing queries and manipulating data.

Topics:

• Intro
• SQL
• DML
• DDL
• Data Types
• Expressions and Operators
• Common SQL Functions