... (Also FWIW, the latest version of
this regexp is now '^([0-9]+.)*[0-9]+$')
Um, that's not gonna do what you want at all. Outside brackets, a dot
is a wildcard. (Regex syntax is a mess :-(.)
regards, tom lane
arg. back to level two of regexpness for me :( I read it as ^[0-9.]+
If I understand your regex needs correctly you want to allow digits separated by dots (like IPv4 octets) but never start w/ or end w/ a dot nor any non digit character other than a dot. If that's the case this may work. I say may because I'm using PCRE syntax and I don't know how much of it PostgreSQL supports.
^(?>\d+)(?>\.\d+)*$
If there is no support for atomic groups you can try this: ^(?:\d++)(?:\.\d++)*$
And if there is no support for greedy quantifiers nor non capturing groups: ^(\d+)(\.\d++)*$