Database [3i Infotech Placement]: Sample Questions 14 - 15 of 294

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Question 14


Describe in Detail


Does PL/SQL support “overloading” . Explain.


  • Yes, PL? SQL supports “overloading” - define more than one function with the same name.
  • Programs different in other ways so that at runtime the PL/SQL engine can figure out which of the programs to execute.
  • PL/SQL does not look only at the referenced name, to resolve a procedure or function call- considerers count and data types of formal parameters.
  • Below some circumstances it is cause the PL/SQL
    • Apply the same action to different kinds or combinations of data.
    • Allow developers to use a program in the most natural and intuitive fashion.
    • Make it easy for developers to specify, unambiguously and simply, the kind of action desired.

Question 15




SNAPSHOTS cannot be refreshed automatically




  • Snapshot refresh group can specify an automatic refresh interval for the group.
  • When setting a group՚s refresh interval, consider the following:
    • The dates or date expressions specifying the refresh interval must evaluate to future time.
    • The refresh interval must be greater than the length of time to perform a refresh.
    • Relative date expressions must evaluate to time relative to the most recent date.
    • Network or system failure can interfere with scheduled group refresh changing evaluation of relative date expression.
    • Explicit date expressions must evaluate to specific points in time, the most recent refresh date.

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