Database [PCS Infotech Placement]: Sample Questions 9 - 10 of 25

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Question 9

Database
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Statement

True-False▾

ROWID is a pseudocolumn of every oracle table

Answer

FALSE

Explanation

  • ROWID pseudocolumn returns the address of the row - A ROWID value uniquely identifies a row within a cluster.
  • Behaves like a table column, is not actually stored in the table.
  • Row numbers and row descriptions automatically stored and is directly accessible.
  • Information in pseudocolumn can be received in queries.
  • Rows in different tables that are stored together in the same cluster the same rowid.
  • Provides quick access to a row- fastest possible access to a row of a given table.

Question 10

Database
Edit

Statement

True-False▾

In SQL SGA area the parser tree and exceptions are stored which are used for multiple applications.

Answer

FALSE

Explanation

  • SGA is used to store incoming data and control the information.
  • Area of memory allocated when an oracle instance starts up.
  • Size and function are controlled by initialization parameters.
  • Contains shared server and background processes.

Common Components in STA

  • Data buffer cache:
    • Cache data and index block for faster access.
  • Shared pool:
    • Cache parsed SQL and PL/SQL statements.
  • Dictionary cache:
    • Information about data dictionary objects.
  • Redo Log Buffer:
    • Committed transactions that are not written to the redo log files.
  • JAVA pool:
    • Caches parsed java program
  • Streams pool:
    • Caches oracle streams objects.
  • Large pool:
    • Used for backup.

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