1. Introduction to Oracle9i: SQL
Data Manipulation
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

2. Introduction to Oracle9i: SQL
Chapter Objectives
Add a record to an existing table
Add a record containing a NULL value to an existing table
Use a subquery to copy records from an existing table
Modify the existing rows within a table
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

3. Introduction to Oracle9i: SQL
Chapter Objectives
Use substitution variables with an UPDATE command
Issue the transaction control statements COMMIT and ROLLBACK
Differentiate between DDL, DML, and transaction control commands
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

4. Introduction to Oracle9i: SQL
Chapter Objectives
Delete records
Differentiate between a shared lock and an exclusive lock
Use the SELECT…FOR UPDATE command to create a shared lock
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

5. Introduction to Oracle9i: SQL
INSERT Command
Used to add rows to existing tables
Identify table in the INSERT INTO clause
Specify data in the VALUES clause
Can only add one row at a time to a table
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

6. Introduction to Oracle9i: SQL
INSERT Command Syntax
Enclose non-numeric data in single quotes
If column list not provided, a value must be assigned to each column in the table
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

7. INSERT Command Example
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

8. Introduction to Oracle9i: SQL
Inserting NULL Value
Omit column name from INSERT INTO clause column list
Substitute two single quotation marks
Use NULL keyword
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

9. Inserting Data from an Existing Table
Substitute subquery for VALUES clause
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

10. Modifying Existing Rows
Modify rows using UPDATE command
Use UPDATE command to:
Add values to an existing row
Change existing values
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

11. Introduction to Oracle9i: SQL
UPDATE Command
UPDATE clause identifies table
SET clause identifies column being changed and new value
Optional WHERE clause specifies row(s) to be changed – if omitted, will update all rows
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

12. Introduction to Oracle9i: SQL
UPDATE Command Syntax
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

13. UPDATE Command Example
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

14. Introduction to Oracle9i: SQL
Note: select query format is determined at the time of the select statement: e.g.
Select title, to_char(pubdate, ‘MONTH DD, YYYY’) “Publication Date”,
to_char (retail, ‘$999.99’) “Retail Price”
from books
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

15. Substitution Variables
Prompts user for value
Identified by ampersand (&) preceding variable name
Can be used to create interactive scripts
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

16. Substitution Variable Example
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

17. Introduction to Oracle9i: SQL
Transaction Control
Results of Data Manipulation Language (DML) are not permanently updated to table until explicit or implicit COMMIT occurs
Transaction control statements can:
Commit data through COMMIT command
Undo data changes through ROLLBACK command
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

18. Introduction to Oracle9i: SQL
COMMIT
Explicit COMMIT occurs by executing COMMIT;
Implicit COMMIT occurs when DDL command is executed or user properly exits system
Permanently updates table(s) and allows other users to view changes
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

19. Introduction to Oracle9i: SQL
ROLLBACK
Used to “undo” changes that have not been committed
Occurs when:
ROLLBACK; is executed
System restarts after crash
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

20. Introduction to Oracle9i: SQL
Deleting Rows//
DELETE command removes a row from a table
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

21. DELETE Command – Omitting WHERE Clause
Omitting WHERE clause removes all rows
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

22. Introduction to Oracle9i: SQL
Table Locks
Prevents users from changing same data or objects
Two types:
Shared – prevents DML operations on portion of table
Exclusive – locks table preventing other exclusive or shared locks
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

23. Introduction to Oracle9i: SQL
Shared Lock
Locks portion of table affected by DML operation
Implicitly occurs during UPDATE or DELETE operations
Explicitly occurs through LOCK TABLE command with SHARE MODE option
Released when COMMIT (implicit or explicit) or ROLLBACK occurs
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

24. Introduction to Oracle9i: SQL
Exclusive Lock
Implicitly locks table for DDL operations - CREATE or ALTER TABLE
Explicitly locked through LOCK TABLE command with EXCLUSIVE MODE option
Released after execution of DDL operation or after user exits system
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

25. SELECT…FOR UPDATE Command
Creates shared lock on retrieved portion of table
Prevents one user from changing a row while another user is selecting rows to be changed
Released through implicit or explicit commit
Chapter insert/manipulate data
Introduction to Oracle9i: SQL

26. SELECT…FOR UPDATE Command – Example
Chapter insert/manipulate data
Introduction to Oracle9i: SQL