"Bruce Momjian" <[EMAIL PROTECTED]> writes: > I realized this when editing the documentation but not clearly. I > noticed that: > > > http://momjian.us/main/writings/pgsql/sgml/textsearch-intro.html#TEXTSEARCH-MATCHING > > tsvector @@ tsquery > tsquery @@ tsvector > text @@ tsquery > text @@ text > > The first two of these we saw already. The form text @@ tsquery is > equivalent to to_tsvector(x) @@ y. The form text @@ text is equivalent > to to_tsvector(x) @@ plainto_tsquery(y). > > was quite odd, especially the "text @@ text" case, and in fact it makes > casting almost required unless you can remember which one is a query and > which is a vector (hint, the vector is first). What really adds to the > confusion is that the operator is two _identical_ characters, meaning > the operator is symetric, and it behave symetric if you cast one side, > but as vector @@ query if you don't.
I find this odd as well. Effectively what we're doing is rather than defining the casting behaviour in a global way we're defining operators specifically for text which do the casts internally. That seems like a bad idea, especially given that other data types implement @@ operators as well. I feel like the right idea is to throw out all but tsvector @@ tsquery and define casts as necessary to get that to work in every (non-inverted) case above. Actually the only case which wouldn't work with just that is a bare 'foo' @@ 'bar' And even that would work fine until you load _int.sql or ltree.sql which define conflicting operators. Separately I feel like we should name this operator something like ~= or =? or something like that. @@ doesn't look like any kind of equality or matching operator and it looks symmetric. We also already have @@ operators which are right-handed unary operators for geometric data types which this is very different from. I would suggest something like =? PS: I thought of a whacky idea which would look neat but be mainly silly. I thought I would mention it anyways though. If we define a unary postfix operator "text ?" which just casted text to tsquery then define a "text = tsquery" operator which does what @@ does. Then you could write queries like: WHERE col = 'foo & bar' ? -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's Slony Replication support! ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
