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Question number: 245

» Database » Oracle



Is the Following Statement True or False?

Constraints cannot be exported through Export command.




  • Export command can export constraints- it can specify whether table constraints should be exported with table data.

  • For import in the normal import order- referential constrains are imported only after all tables are imported.

  • This sequence prevents errors that occur when constraints can fail when data has not been fully imported.

  • When an error occurs, import generates an error message for failed row and continues importing other rows in the table.

  • Constrain export can be disabled to avoid this.

Question number: 246

» Basic CS » Data Structures

Essay Question▾

Describe in Detail

Define of common data structures:



General purpose of linked list

Singly vs. doubly linked lists.


  • Stack:

    • Stack is a linear data structure which follows a particular order in which the operations are performed.

    • The order LIFO (Last In First Out) or FILO (First In Last Out).

  • Queue:

    • Linear data structure.

    • Additions are made at the end or tail of the queue while removals are made from the front or head of the queue.

    • Queue is referred to FIFO structure for its First in First Out Access.

  • General purpose of linked list

    • A linear data structure

    • Common data structure consisting of group of nodes in a sequence divided in two parts.

    • Each node consists of its own data and the address of the next node and forms a chain.

    • Used to create trees and graphs.

  • Singly vs. doubly linked lists.

Difference between singly and doubly linked list

Difference between singly and doubly linked list

Singly Linked List

Doubly Linked List

Allow one way travel- can access successor

Allows two way travel using two pointers next and previous

Uses less memory per node

Uses more memory per node than singly linked list

Complexity of insertion and deletion at known position is O (n)

Complexity of Insertion and Deletion at known position is O (1).

There is a allowing delete from a singly-linked list in O (1), but the list must be circular

Used in places where singly-linked lists would not work but they require slightly more “housekeeping”, and are slightly less efficient on insertions as the result

Each node contains at least two parts:

  1. Info
  2. link

Each node contains at least three parts:

  1. Info
  2. Link to next node
  3. Link to previous node.