Indexes are created to enforce uniqueness on columns and to enable fast retrieval by column values.

More Questions from Managing Databases with Oracle

• Oracle does NOT support a CASCADE UPDATE constraint.
• You can use the DROP statement to remove structures from the database.
• SQL*Plus is a text editor.
• When you type into SQL*Plus and press enter, the statement will be finished and executed.
• Oracle directly supports the definition of surrogate keys.
• Sequences guarantee valid surrogate key values.
• Oracle, the world's most popular DBMS, is powerful and robust, running on many different operating systems.
• You can check on the status of tables with the DESCRIBE or DESC command.
• Oracle allows the ORDER BY clause in view definitions.
• The semicolon terminates a SQL statement (and executes it).

Discussion & Comments