3i Infotech Placement: Sample Questions 781 - 782 of 1245

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Question 781

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Describe in Detail

Essay▾

OOT uses

Explanation

7 principles that form the foundation for OOT or Object Oriented Technology are:

  • Abstraction.

    To address complexity in software development.

  • Encapsulation:

    Hiding design details in the object implementation - for future upgradation.

  • Modularity:

    Partitioning a program into logically separated and defined components with defined interactions and limited access to data.

  • Hierarchy:

    Single inheritance or multiple inheritance allowing functionality reuse.

  • Typing:

    Enforcement of the class of an object so that objects of different types are not interchanged.

  • Concurrency:

    Carrying out several events simultaneously.

  • Persistence:

    Making object exist even after program ends- so work can continue from where it was stopped.

Question 782

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Describe in Detail

Essay▾

Difference between “VARCHAR” and “VARCHAR2” datatypes.

Explanation

Difference between Varchar and varchar2
VarcharVarchar2
Variable length character stringVariable length character string2
In Oracle, not recommended to be used currently. VARCHAR might be defined as a separate data type for variable-length character strings in the futureIn Oracle, this datatype is used to store a variable length character string with a maximum of 4000 bytes.
VARCHAR can store up to 2000 bytes of charactersVARCHAR2 can store up to 4000 bytes of characters.
If we declare datatype as VARCHAR then it will occupy space for NULL values.In case of VARCHAR2 datatype, it will not occupy any space.
If you enter value less than 10, it utilize total 10 spaces.If you enter value, less than 10 then remaining space is not utilize.

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