78. Difference between EQUI JOIN and OUTER JOIN ?
EQUI JOIN returns rows from both the tables provided they both have the same
column_name
in the where clause. The symbol (=) represents the EQUI JOIN.
For OUTER JOIN see previous answer.
79. Define NORMALIZATION ?
NORMALIZATION is the process of putting things right, making them normal. It is a
part of analysis necessary to understand a business, and build a useful application.
The normalization of data ensures
a] Minimization of duplication of data.
b] Providing flexibility to support different funtional requirements.
c] Enabling the model to be translated to database design.
STEPS INVOLVED IN NORMALIZATION
1] Ensure that all the ENTITIES are uniquely identified by a combination of attributes.
2] Remove repeated attributes or group of attributes, to place the entities in the first
normal form.
3] Remove attributes that are dependent on only part of the identifier.
4] Remove attributes that are dependent on attributes which are not part of the identifier.
85. What is the Purpose of ERASE command ?
ERASE removes an indicated Global variable & releases the memory associated with it
What is LookUp table ?
When a foreign key exists in a table, the foreign key's table is sometimes referred to as a
lookup table
. The DEPARTMENT table in our example is a lookup table for the EMPLOYEE
table. The value of an employee's department can be looked up in the DEPARTMENT table.
MULTIPLE CHOICE QUESTIONS
11. The purpose of defining an index is
(A) Enhance Sorting Performance (B) Enhance Searching Performance
(C) Achieve Normalization (D) All of the above
12. A transaction does not necessarily need to be
(A) Consistent (B) Repeatable (C) Atomic (D) Isolated
13. To group users based on common access permission one should use
(A) User Groups (B) Roles (C) Grants (D) None of the above
14. PL/SQL uses which of the following
(A) No Binding (B) Early Binding (C) Late Binding (D) Deferred Binding
15. Which of the constraint can be defined at the table level as well as at the column level
(A) Unique (B) Not Null (C) Check (D) All the above
16. To change the default date format in a SQLPLUS Session you have to
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