COMPUTER SCIENCE AND ENGINEERING
SQL
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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NULL
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Empty
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0
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Garbage Value
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Detailed explanation-1: -NULL values represent missing unknown data. By default, a table column can hold NULL values.
Detailed explanation-2: -The default null value for null numeric fields is 0 (zero). The default null value for null alpha fields is either a single blank space ( ) or multiple blank spaces to length, depending on the field’s requirements.
Detailed explanation-3: -Default values can be NULL, or they can be a value that matches the data type of the column (number, text, date, for example).
Detailed explanation-4: -If we do not provide any value for column allow NULL values, SQL Server assumes NULL as default value.
Detailed explanation-5: -By default, a column can hold NULL values. 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.