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- Should "and" be "and/or"? If so, I'll +1.paxdiablo– paxdiablo2009-02-09 06:31:22 +00:00Commented Feb 9, 2009 at 6:31
- I'm not an expert in db theory but you sound right. I'll check and edit.Learning– Learning2009-02-09 06:34:15 +00:00Commented Feb 9, 2009 at 6:34
- "Null values (distinct from an empty character string or a string of blank characters and distinct from zero or any other number) are supported in a fully relational DBMS for representing missing information and inapplicable information in a systematic way, independent of the data type" (cont..)Learning– Learning2009-02-09 06:37:05 +00:00Commented Feb 9, 2009 at 6:37
- It may be applicable but missing, for example, I decline to tell you my wage. Or it may be inapplicable, for example, I'm a contractor so my annual wage column is NULL but my hourly rate column is not.paxdiablo– paxdiablo2009-02-09 06:37:22 +00:00Commented Feb 9, 2009 at 6:37
- So from the context , you are right. (btw : this is from Codd's 12 rules : scs.carleton.ca/~bertossi/integra08/material/Codd12Rules.txt)Learning– Learning2009-02-09 06:37:52 +00:00Commented Feb 9, 2009 at 6:37
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