How can write regular expressions to match names like 'José' in postgres.. In other words I need to setup a constraint to check that only valid names are entered, but want to allow unicode characters also.
Regular expressions, unicode style have some reference on this. But, it seems I can't write it in postgres.
If it is not possible to write a regex for this, will it be sufficient to check only on client side using javascript
PostgreSQL doesn't support character classes based on the Unicode Character Database like .NET does. You get the more-standard [[:alpha:]] character class, but this is locale-dependent and probably won't cover it.
You may be able to get away with just blacklisting the ASCII characters you don't want, and allowing all non-ASCII characters. eg something like
[^\s!"#$%&'()*+,\-./:;<=>?\[\\\]^_`~]+
(JavaScript doesn't have non-ASCII character classes either. Or even [[:alpha:]].)