Re: Why is there a tsquery data type?

Tom Lane wrote:
> Gregory Stark <stark(at)enterprisedb(dot)com> writes:
> > How would that happen if there wasn't a tsquery type?
>
> I don't think Bruce is suggesting that the search operand can really
> be plain text (or if he is, he's nuts). The question here is whether

Yes, that is what I was suggesting because as I mentioned TEXT already
functions fine as tsquery.

> there's really a need for a distinction between tsvector and tsquery
> datatypes; could we have tsvector serve both purposes instead?
>
> I can see that there are differences: tsquery can tell the difference
> between "x AND y" and "x OR y", whereas tsvector just knows "x, y".
> A superset datatype that can do both is certainly possible, but whether
> it's practical, or would be easier to use than the current design,
> I dunno.

Because of the special behavior of & and |, I assume tsquery and
tsvector cannot be the same data type.

> Perhaps a suitable analogy is regexp pattern matching. Traditionally
> regexps are conceived of as strings, but if they'd originated in more
> strongly typed languages than they did, they'd certainly be thought
> of as a distinct data type. Had we implemented ~ as taking a right
> operand of type 'regexp', we could win on a number of levels: entry-time
> syntax checking for regexps, and a precompiled internal representation,
> for instance. For regexps it seems clear to me that the target text
> string and the pattern really are different datatypes, and fuzzing that
> distinction is not an improvement.

Yes, this is a good analogy.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://www.enterprisedb.com

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