xix
Situations Where Hashing Is Not Advantageous ...................................................................... 23-2
Creating Hash Clusters ........................................................................................................................ 23-2
Creating a Sorted Hash Cluster..................................................................................................... 23-3
Creating Single-Table Hash Clusters ........................................................................................... 23-6
Controlling Space Use Within a Hash Cluster............................................................................ 23-6
Estimating Size Required by Hash Clusters................................................................................ 23-8
Altering Hash Clusters......................................................................................................................... 23-9
Dropping Hash Clusters ...................................................................................................................... 23-9
Hash Clusters Data Dictionary Views .............................................................................................. 23-9
24 Managing Views, Sequences, and Synonyms
Managing Views.................................................................................................................................... 24-1
About Views .................................................................................................................................... 24-1
Creating Views ................................................................................................................................ 24-2
Replacing Views.............................................................................................................................. 24-4
Using Views in Queries ................................................................................................................. 24-5
Updating a Join View ..................................................................................................................... 24-6
Altering Views............................................................................................................................... 24-12
Dropping Views ............................................................................................................................ 24-12
Managing Sequences.......................................................................................................................... 24-13
About Sequences ........................................................................................................................... 24-13
Creating Sequences....................................................................................................................... 24-13
Altering Sequences........................................................................................................................ 24-14
Using Sequences............................................................................................................................ 24-14
Dropping Sequences..................................................................................................................... 24-17
Managing Synonyms.......................................................................................................................... 24-17
About Synonyms........................................................................................................................... 24-17
Creating Synonyms....................................................................................................................... 24-18
Using Synonyms in DML Statements ....................................................................................... 24-18
Dropping Synonyms..................................................................................................................... 24-19
Views, Synonyms, and Sequences Data Dictionary Views........................................................ 24-19
25 Repairing Corrupted Data
Options for Repairing Data Block Corruption................................................................................ 25-1
About the DBMS_REPAIR Package .................................................................................................. 25-2
DBMS_REPAIR Procedures........................................................................................................... 25-2
Limitations and Restrictions.......................................................................................................... 25-2
Using the DBMS_REPAIR Package................................................................................................... 25-2
Task 1: Detect and Report Corruptions ....................................................................................... 25-3
Task 2: Evaluate the Costs and Benefits of Using DBMS_REPAIR.......................................... 25-4
Task 3: Make Objects Usable ......................................................................................................... 25-5
Task 4: Repair Corruptions and Rebuild Lost Data................................................................... 25-5
DBMS_REPAIR Examples................................................................................................................... 25-5
Examples: Building a Repair Table or Orphan Key Table ........................................................ 25-6
Example: Detecting Corruption .................................................................................................... 25-7
Example: Fixing Corrupt Blocks ................................................................................................... 25-8