Monday, 9 February 2015

oracle ddeveloper questions for 3 years experience (Page 4)

Below are some important Oracle Developer interview questions which are asked in most MNC company interviews for beginners or professionals.

31. What is cluster Key?
The related columns of the tables in a cluster is called the Cluster Key.

32. What is Index Cluster?
A Cluster with an index on the Cluster Key.

33. What is Hash Cluster?
A row is stored in a hash cluster based on the result of applying a hash function to the row's cluster key value. All rows with the same hash key value are stores together on disk.

34. What is the maximum number of CHECK constraints that can be defined on a column?
No Limit.

35. 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.

36. What is self-referential integrity constraint?
If a foreign key reference a parent key of the same table is called self-referential integrity constraint.

37. What is Row Chaining?
In Circumstances, all of the data for a row in a table may not be able to fit in the same data block. When this occurs , the data for the row is stored in a chain of data block (one or more) reserved for that segment.

38. Explain an Extent?
An Extent is a specific number of contiguous data blocks, obtained in a single allocation, used to store a specific type of information.

39. Explain a Segment?
A segment is a set of extents allocated for a certain logical structure.

40. Explain What are the different type of Segments?
Data Segment, Index Segment, Rollback Segment and Temporary Segment.
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