Wednesday, January 22, 2014

Oracle DBA Q & A page - 8

ORACLE DBA INTERVIEW QUESTIONS AND ANSWERS

                                                
                                                                 Page – 8

71. What are mutating tables?

When a table is in state of transition it is said to be mutating. eg If a row has been deleted then the table is said to be mutating and no operations can be done on the table except select

72. What is rollback segment?

A database contains one or more rollback segments to temporarily store "undo" information

73. What is  datafile?

Every Oracle database has one or more physical data files. A database's data files contain all the database data. The data of logical database structures such as tables and indexes is physically stored in the data files allocated for a database

74. What background process refreshes materialize views?

The Job Queue Processes

75. Can we rename the table tablespace?

No, this is listed as Enhancement Request 148742. Workaround:
Export all of the objects from the tablespace
Drop the tablespace including contents
Recreate the tablespace
Import the objects


76. What is  library?

A library is a collection of subprograms including user named procedures, functions and packages

77. What  you mean by program global area (PGA)?

It is area in memory that is used by a Single Oracle User Process

78. What is an OLE?

Object Linking & Embedding provides you with the capability to integrate objects from many Ms-Windows applications into a single compound document creating integrated applications enables you to use the features form

79. What  you mean by display item?

Display items are similar to text items but store only fetched or assigned values. Operators cannot navigate to a display item or edit the value it contains

80. How can we avoid indexes?

TO make index access path unavailable - Use FULL hint to optimizer for full table scan - Use INDEX or AND-EQUAL hint to optimizer to use one index or set to indexes instead of another. - Use an expression in the Where Clause of the SQL

                                               Page  1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10

No comments:

Post a Comment