'null' values

From: Ria Vandenberghe <rvdbergh_at_egidius.rug.ac.be>
Date: 7 Mar 1995 08:29:57 GMT
Message-ID: <3jh5i5$k55_at_infoserv.rug.ac.be>

I am looking for information about (a) the internal representation of 'null' values and (b) the treatment of 'null' values, in the major commercial relational DBMSs.

(a) How are 'null' values *internally* represented in the DBMS ?
e.g. by means of some reserved value in the range of possible values, or by means of some invalid value, for each type of field supported by the DBMS; by means of some (hidden) extra bit/byte; ....

(b) As to the treatment of 'null' values, does the DBMS deviate from the
SQL2 standard in any way ?

Many thanks in advance for your replies, Regards,

Ria.

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Ria Vandenberghe                 Ria.Vandenberghe_at_rug.ac.be

UNIVERSITY OF GHENT (BELGIUM) - Computer Science Laboratory Technologiepark-Zwijnaarde 9, B-9052 ZWIJNAARDE, BELGIUM

tel: +32/9/264.55.10                   fax: +32/9/264.58.42

Received on Tue Mar 07 1995 - 09:29:57 CET