I know NULL is not zero… nor it is empty string. But then what is the value of NULL… which the system keeps, to identify it?
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I know NULL is not zero… nor it is empty string. But then what is the value of NULL… which the system keeps, to identify it?
I believe that for each column that allow nulls, the rows have a null bitmap. If the row in the specified column is null the bit in the bitmap is 1 otherwise is 0.