Sams Teach Yourself SQL in 24 Hours

By Ron Plew and Ryan Stephens

• Table of Contents
  • Copyright
  • About the Authors
  • Acknowledgments
  • Tell Us What You Think!
  • Introduction
  • Part I: A SQL Concepts Overview
  • Hour 1. Welcome to the World of SQL
  • Part II: Building Your Database
  • Hour 2. Defining Data Structures
  • Hour 3. Managing Database Objects
  • Hour 4. The Normalization Process
  • Hour 5. Manipulating Data
  • Hour 6. Managing Database Transactions
  • Part III: Getting Effective Results from Queries
  • Hour 7. Introduction to the Database Query
  • Hour 8. Using Operators to Categorize Data
  • Hour 9. Summarizing Data Results from a Query
  • Hour 10. Sorting and Grouping Data
  • Hour 11. Restructuring the Appearance of Data
  • Hour 12. Understanding Dates and Times
  • Part IV: Building Sophisticated Database Queries
  • Hour 13. Joining Tables in Queries
  • Hour 14. Using Subqueries to Define Unknown Data
  • Hour 15. Combining Multiple Queries into One
  • Part V: SQL Performance Tuning
  • Hour 16. Using Indexes to Improve Performance
  • Hour 17. Improving Database Performance
  • Part VI: Using SQL to Manage Users and Security
  • Hour 18. Managing Database Users
  • Hour 19. Managing Database Security
  • Part VII: Summarized Data Structures
  • Hour 20. Creating and Using Views and Synonyms
    • What Is a View?
    • Creating Views
    • Dropping a View
    • What Is a Synonym?
    • Summary
    • Q&A
    • Workshop
  • Hour 21. Working with the System Catalog
  • Part VIII: Applying SQL Fundamentals in Today's World
  • Hour 22. Advanced SQL Topics
  • Hour 23. Extending SQL to the Enterprise, the Internet, and the Intranet
  • Hour 24. Extensions to Standard SQL
  • Part IX: Appendixes
  • Appendix A. Common SQL Commands
  • Appendix B. Using MySQL for Exercises
  • Appendix C. Answers to Quizzes and Exercises
  • Appendix D. CREATE TABLE Statements for Book Examples
  • Appendix E. INSERT Statements for Data in Book Examples
  • Appendix F. Glossary
  • Appendix G. Bonus Exercises

What Is a Synonym?

A synonym is merely another name for a table or a view. Synonyms are usually created so that a user can avoid having to qualify another user's table or view to access the table or view. Synonyms can be created as PUBLIC or PRIVATE. A PUBLIC synonym can be used by any user of the database; a PRIVATE synonym can be used only by the owner and any users that have been granted privileges.

Managing Synonyms

Synonyms are either managed by the database administrator (or another designated individual) or by individual users. Because there are two types of synonyms, PUBLIC and PRIVATE, different system-level privileges may be required to create one or the other. All users can generally create a PRIVATE synonym. Typically, only a DBA or privileged database user can create a PUBLIC synonym. Refer to your specific implementation for required privileges when creating synonyms.

Creating Synonyms

The general syntax to create a synonym is as follows:

   
CREATE [PUBLIC|PRIVATE] SYNONYM SYNONYM_NAME FOR TABLE|VIEW

You create a synonym called CUST, short for CUSTOMER_TBL, in the following example. This frees you from having to spell out the full table name.

   
   

   CREATE SYNONYM CUST FOR CUSTOMER_TBL;

   
Synonym created.


   SELECT CUST_NAME

   FROM CUST;

   
CUST_NAME
----------------------------
LESLIE GLEASON
NANCY BUNKER
ANGELA DOBKO
WENDY WOLF
MARYS GIFT SHOP
SCOTTYS MARKET
JASONS AND DALLAS GOODIES
MORGANS CANDIES AND TREATS
SCHYLERS NOVELTIES
GAVINS PLACE
HOLLYS GAMEARAMA
HEATHERS FEATHERS AND THINGS
RAGANS HOBBIES INC
ANDYS CANDIES
RYANS STUFF
15 rows selected.

It is also a common practice for a table owner to create a synonym for the table to which you have been granted access so that you do not have to qualify the table name by the name of the owner:

   
   

   CREATE SYNONYM PRODUCTS_TBL FOR USER1.PRODUCTS_TBL;

   
Synonym created.

Dropping Synonyms

Dropping synonyms is like dropping most any other database object. The general syntax to drop a synonym is as follows:

   
DROP [PUBLIC|PRIVATE] SYNONYM SYNONYM_NAME

The following is an example:

   
   

   DROP SYNONYM CUST;

   
Synonym dropped.

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