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Data Definition Language (SQL DDL)

The Data Definition Language is intended for creating, modifying and deleting database objects. Major objects of a relational database are tables. Let’s start with them.

There are two types of tables – permanent (base) and temporary ones. Temporary tables exist only for the duration of the user session they have been created in. If these tables aren’t deleted explicitly during the session, they will be automatically removed from memory when it ends. Base tables are intended for long-term information storage in the database.


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