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ORACLE Interview Questions and Answers
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822. What is mean by Program Global Area (PGA) ?
It is area in memory that is used by a Single Oracle User Process.
823. What is hit ratio ?
It is a measure of well the data cache buffer is handling requests for data. Hit Ratio = (Logical Reads - Physical Reads - Hits Misses)/ Logical Reads.
824. How do u implement the If statement in the Select Statement
We can implement the if statement in the select statement by using the Decode statement.
e.g select DECODE (EMP_CAT,'1','First','2','Second'Null);
Here the Null is the else statement where null is done .
825. How many types of Exceptions are there
There are 2 types of exceptions. They are
a) System Exceptions
e.g. When no_data_found, When too_many_rows
b) User Defined Exceptions
e.g. My_exception exception
When My_exception then
826. What are the inline and the precompiler directives
The inline and precompiler directives detect the values directly
827. How do you use the same lov for 2 columns
We can use the same lov for 2 columns by passing the return values in global values and using the global values in the code
828. How many minimum groups are required for a matrix report
The minimum number of groups in matrix report are 4
829. What is the difference between static and dynamic lov
The static lov contains the predetermined values while the dynamic lov contains values that come at run time
830. How does one manage Oracle database users? (for DBA
Oracle user accounts can be locked, unlocked, forced to choose new passwords, etc. For example, all accounts except SYS and SYSTEM will be locked after creating an Oracle9iDB database using the DB Configuration Assistant (dbca). DBA's must unlock these accounts to make them available to users.
Look at these examples:
ALTER USER scott ACCOUNT LOCK -- lock a user account
ALTER USER scott ACCOUNT UNLOCK; -- unlocks a locked users account
ALTER USER scott PASSWORD EXPIRE; -- Force user to choose a new password
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