Re: BUG #4525: substring with this pattern works in 8.3.1; does not work in 8.3.4

On Wed, Nov 12, 2008 at 06:45:27PM +0000, chris wood wrote:
> I apologize in advance for not testing on 8.3.5, but that would be very
> difficult for me.
> I e-mailed this same problem from chris(dot)wood(at)bookitnow(dot)ca and it got
> blocked

http://www.postgresql.org/docs/current/interactive/release-8-3-2.html
...
Fix a corner case in regular-expression substring matching
(substring(string from pattern)) (Tom)

The problem occurs when there is a match to the pattern overall but the
user has specified a parenthesized subexpression and that subexpression
hasn't got a match. An example is substring('foo' from 'foo(bar)?').
This should return NULL, since (bar) isn't matched, but it was
mistakenly returning the whole-pattern match instead (ie, foo).
...

so basically - it is that the code that worked before is considered to
be bad.

how to fix it:
1. change the regexpin substring to:
'^[0-9]{10}(?:,[0-9]{10})*$'

2. change check to:
CHECK ((public_phone ~ '^([0-9]{10}(,[0-9]{10})*)?$')));

choose whichever you prefer.

Best regards,

depesz

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