Beginning SQL

Chapter 12
Summary
Database security is a subject that simply cannot be ignored. The SQL standard contains statements
designed to enforce privileges to use objects in the database, primarily tables and views but also other
objects. This chapter covered the following topics:
❑ SQL security centers around users (or user IDs) that can grant privileges on database objects
such as tables and views.
❑ Data in specific tables and views, and even columns of specific tables and views, should be
available to some users but not available to others.
❑ Views may be required to restrict access to specific columns in some DBMSs where an extension
to the SELECT syntax is not available.
❑ The GRANT statement grants SELECT, UPDATE, INSERT, and DELETE privileges to specific users.
❑ The GRANT OPTION allows a user to extend the privileges she has been granted down the line to
other users.
❑ The REVOKE statement is used to revoke privileges granted to a user as well as revoke the GRANT
OPTION itself.
In the next chapter, you learn about optimizing your database and how to write efficient SQL queries to
speed up data retrieval.
Exercises
1. Create DataEntry, Supervisor, and Management groups.
2. Create users John, Joe, Fred, Lynn, Amy, and Beth.
3. Add John, Joe, and Lynn to the DataEntry group, add Fred to the Supervisor group, and add
Amy and Beth to the Management group.
4. Give the DataEntry group SELECT, INSERT, and UPDATE privileges on the Attendance table.
5. Give the Supervisor group SELECT and DELETE privileges on the Attendance table.
6. Give the Management group SELECT privileges on the Attendance table.
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