COMPUTER SCIENCE AND ENGINEERING
SQL
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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This constraint cannot accept NULL values.
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CHECK
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NOT NULL
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PRIMARY KEY
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UNIQUE
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Explanation:
Detailed explanation-1: -The NOT NULL constraint enforces a column to NOT accept NULL values. This enforces a field to always contain a value, which means that you cannot insert a new record, or update a record without adding a value to this field.
Detailed explanation-2: -We can remove a NOT NULL constraint from a column of an existing table by using the ALTER TABLE statement.
Detailed explanation-3: -Use the NULL keyword to specify that a column can store the NULL value for its data type. This implies that the column need not receive any value during insert or update operations. The NULL constraint is logically equivalent to omitting the NOT NULL constraint from the column definition.
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