Question 46 :
What does a Control file Contain ?
A Control file records the physical structure of the database. It contains the following information.
Names and locations of a database's files and redolog files.
Time stamp of database creation.
Question 47 :
What is difference between UNIQUE constraint and PRIMARY KEY constraint ?
A column defined as UNIQUE can contain Nulls while a column defined as PRIMARY KEY can't contain Nulls.
Question 48 :
What is Index Cluster ?
A Cluster with an index on the Cluster Key
Question 49 :
When does a Transaction end ?
When it is committed or Rollbacked.
Question 50 :
What is the effect of setting the value "ALL_ROWS" for OPTIMIZER_GOAL parameter of the ALTER SESSION command ? What are the factors that affect OPTIMIZER in choosing an Optimization approach ?
The OPTIMIZER_MODE initialization parameter Statistics in the Data Dictionary the OPTIMIZER_GOAL parameter of the ALTER SESSION command hints in the statement.