69. List the Optional Flexible Architecture (OFA) of Oracle database? How can we organize the tablespaces in Oracle Database to have maximum performance?
SYSTEM - Data dictionary tables.
DATA - Standard operational tables.
DATA2- Static tables used for standard operations
INDEXES - Indexes for Standard operational tables.
INDEXES1 - Indexes of static tables used for standard operations.
TOOLS - Tools table.
TOOLS1 - Indexes for tools table.
RBS - Standard Operations Rollback Segments,
RBS1,RBS2 - Additional/Special Rollback segments.
TEMP - Temporary purpose tablespace
TEMP_USER - Temporary tablespace for users.
USERS - User tablespace.

70. How will you force database to use particular rollback segment?
SET TRANSACTION USE ROLLBACK SEGMENT rbs_name.

71. What is meant by free extent?
A free extent is a collection of continuous free blocks in tablespace. When a segment is dropped its extents are reallocated and are marked as free.

72.Which parameter in Storage clause will reduce number of rows per block?
PCTFREE parameter
Row size also reduces no of rows per block.

73. What is the significance of having storage clause?
We can plan the storage for a table as how much initial extents are required, how much can be extended next, how much % should leave free for managing row updating, etc.,