Re: Binding of JDBC prepared statement parameters

[Daniel Dittmar]

Sven K�hler wrote:

    The dreaded three valued logic monster rears it's head again:
    1 <> NULL => NULL
    NOT NULL => NULL


I haven't catched the argument you used.
What do you mean with NOT NULL => NULL?

1 <> NULL doesn't evaluate to false, it evaluates to NULL, that's why it's called three valued logic (true, false, NULL)

Simply read NULL as 'unknown'.

NULL and TRUE => NULL
NULL and FALSE => FALSE
NULL or TRUE => TRUE
NULL or FALSE => NULL
not NULL => NULL

http://www.cc.utah.edu/cgi-bin/cgiwrap/nahaj/threeval.cgi lets you play around with this.

Daniel Dittmar

--
Daniel Dittmar
SAP DB, SAP Labs Berlin
[EMAIL PROTECTED]
http://www.sapdb.org



_______________________________________________
sapdb.general mailing list
[EMAIL PROTECTED]
http://listserv.sap.com/mailman/listinfo/sapdb.general