SQL INTERVIEW QUESTION & ANSWERS
91. |
What are the conditions to achieve the normalization? |
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There are few conditions to achieve the normalization :- There should be a unique row identifier.
- A table should store only data for a single type of entity.
- A table should avoid columns which can be null–able.
- A table should avoid duplication of data and columns.
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92. |
Can a trigger be altered? |
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No, the trigger must be replaced or re–created |
93. |
Which clauses in an UPDATE statement can contain a subquery? |
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WHERE and SET |
94. |
What option can be used when creating a view from a view to check integrity
constraints? |
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The WITH CHECK OPTION |
95. |
What is the difference between Count and Count (*)? |
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- Count : Counts the number of non-null values.
- Count (*) : Counts the number of rows in the table, including null values and duplicates.
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