Sql Interview Question and Answers
| 81. |
What is De-normalization? |
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De-normalization is the process of attempting to optimize the performance of a database by adding redundant data.
De-normalization is a technique to move from higher to lower normal forms of database modeling in order to speed up database access. |
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| 82. |
What is referential integrity? |
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Referential integrity refers to the consistency that must be maintained between primary and foreign keys, i.e. every foreign key value must have a corresponding primary key value. |
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| 83. |
What is the difference between static and dynamic SQL? |
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Static SQL is hard-coded in a program when the programmer knows the statements to be executed.
For dynamic SQL the program must dynamically allocate memory to receive the query results. |
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| 84. |
Define Unique Key? |
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Unique key is a one or more column that must be unique for each row of the table.
It is similar to primary key. Primary key column will not accept a null. Whereas the unique key column will accept a null values.
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| 85. |
Define Synonym? |
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Synonym is an alternative method to creating a view that includes the entire table or view from another user it to create a synonym.
A synonym is a name assigned to a table or view that may thereafter be used to refer to it. |
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Gk Questions with Answers