1. Refining the Server Model

2. Adding New Tables New Table New View New Snapshot New Cluster New Column New Man FK New Opt FK

3. Add a Foreign Key

4. Create Index for FK DDT Automatically Creates Index for FK

5. Other Columns to Index Key columns Columns used frequently in queries Columns with many distinct values Guidelines: –Start with the least number of indexes –Add indexes as the data grows –Check both query and DML perfomance

6. Choosing the Number of Indexes More indexes = slower insert and delete Concatenated indexes can help Queries: NAME = 'SMITH'; JOB LIKE 'SALES%' AND NAME = 'SMITH'; JOB = 'CLERK' AND NAME = 'SMITH' AND HIREDATE > '1-JUN-98'; HIREDATE = '31-DEC-98'; Indexes: NAMEJOBHIREDATE NAME JOB HIREDATE

7. Oracle Sequence Database object: –Generates unique numbers –Minimizes contention Gaps in sequence 3 2 1

8. Adding Surrogate Key Create a Sequence Assign to Column Create Key

9. DDT Surrogate Keys Automatically creates key Automatically creates sequence Automatically assigns sequence to key column

10. Oracle Sequences Efficient Have Gaps –Rolled back transactions do not return used sequence numbers

11. Eliminating the Gaps IDENTIFIERLAST_NAME New row 2017 2016SMITH HAMBURG CG_CODE_CONTROLS EMPLOYEES CC_DOMAIN CC_NEXT VALUE CC_INCREMENT EMP_SEQ1 2017 1 EMP_SEQ1 1 CC_DOMAIN CC_NEXT VALUE CC_INCREMENT EMP_SEQ1 2018 1 EMP_SEQ1 1

12. Creating a Code Control Sequence Sequence Definitions Create Sequence: Name ? Name of the sequence Purpose of the sequence Sequence typeORACLE sequence Code control sequence 1 2 3

13. RE_IDLINE_NO 11 2 1 RENTAL_ITEMS 2 2 1 2 Sequence Within Parent RE_ID 1212 RENTALS Generate a value within the context of the parent record

14. Creating a Sequence Within a Parent Set AutoGen Type to Seq in Parent Column Properties Derivation Autogen Type … Seq in Parent

15. Choosing a Method Oracle sequence: –Sequential values with gaps –Recommended Code control sequence: –Databases other than Oracle –Sequential values without gaps –Contention can be tolerated Sequence within a parent: –Minimal number of detail records