Computer Tutorials
Earn Money From Internet
Cheap Freelancers
Ask An Expert
Register Cheap Domain
Data Recovery
Best Mutual Funds
Trading Forex Online
Cheap Web Hosting
Ajax Tutorials
Cheap Cell Phone Plans
Free Mobile Learning
Job Portal
Photoshop Tutorials
Cheap Jewelry
Cheapest Air Travel
Oracle Interview Questions And Answers
|
Page 7 of 95
59. What are the Limitations of a CHECK Constraint ? The condition must be a Boolean expression evaluated using the values in the row being inserted or updated and can't contain subqueries, sequence, the SYSDATE,UID,USER or USERENV SQL functions, or the pseudo columns LEVEL or ROWNUM. 60. What is the maximum number of CHECK constraints that can be defined on a column ? No Limit. SYSTEM ARCHITECTURE : 61. What constitute an ORACLE Instance ? SGA and ORACLE background processes constitute an ORACLE instance. (or) Combination of memory structure and background process. 62. What is SGA ? The System Global Area (SGA) is a shared memory region allocated by ORACLE that contains data and control information for one ORACLE instance. 63. What are the components of SGA ? Database buffers, Redo Log Buffer the Shared Pool and Cursors. 64. What do Database Buffers contain ? Database buffers store the most recently used blocks of database data. It can also contain modified data that has not yet been permanently written to disk. 65. What do Redo Log Buffers contain ? Redo Log Buffer stores redo entries a log of changes made to the database. 66. What is Shared Pool ? Shared Pool is a portion of the SGA that contains shared memory constructs such as shared SQL areas. 67. What is Shared SQL Area ? A Shared SQL area is required to process every unique SQL statement submitted to a database and contains information such as the parse tree and execution plan for the corresponding statement. 68. What is Cursor ? A Cursor is a handle ( a name or pointer) for the memory associated with a specific statement. 69. What is PGA ? Program Global Area (PGA) is a memory buffer that contains data and control information for a server process. 70. What is User Process ? A user process is created and maintained to execute the software code of an application program. It is a shadow process created |