How does DB2 store NULL physically?

DB2 INTERVIEW QUESTIONS

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How does DB2 store NULL physically?

as an extra-byte prefix to the column value. physically, the nul prefix is Hex ’00’ if the value is present and Hex ‘FF’ if it is not.

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Other Interview Questions

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• How do you find the maximum value in a column in DB2?
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• What is the restriction on using UNION in embedded SQL?
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• Is BETWEEN inclusive of the range values specified? –
• What is 'LIKE' used for in WHERE clause? What are the wildcard characters? –
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• What is the meaning of underscore ( ‘_’ ) in the LIKE statement? –
• What do you accomplish by GROUP BY ... HAVING clause? ––
• Consider the employee table with column PROJECT nullable. How can you get a list of employees who are not assigned to any project?
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• How would you retrieve rows from a DB2 table in embedded SQL? –
• How do you specify and use a cursor in a COBOL program? –
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• What are the contents of a DCLGEN?
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• EXPLAIN has output with MATCHCOLS = 0. What does it mean? –
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• How does DB2 determine what lock-size to use?
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• How does DB2 store NULL physically?
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