Re: [hibernate-dev] HQL and spatial

It is true that not all applications use spatial, or even that DB’s > support (all) spatial functions. But it would help to ensure consistency in > the available dialects. Now this consistency is tested for in the > integration tests, so not having this at the grammar isn’t a big problem. > Its up to you. We can add it to the grammar and simply have it throw exceptions if those functions are not understood. Support for spatial literals would be a great plus. In my opinion, the > best candidate for HQL spatial literals is the Postgis EWKT format ( > http://postgis.net/docs/manual-2.1/using_postgis_dbmanagement.html#EWKB_EWKT), > which is a sane, and popular extension of the purely 2D WKT standard. It > is supported in the geolatte-geom library and many others. I can help by > writing a grammar for this. > What I have done thus far in SQM grammars is to borrow from the idea of "JDBC escape syntax". So for example, to define a timestamp literal one would say `{ts '2015-10-10 ...'}` There is also at least one HQL syntax change that would help implement > spatial functions: function invocations that evaluate to boolean should be > regarded as valid boolean expressions. The HQL currently doesn’t seem to > allow this, so I needed to wrap them in equality expressions. But then > MySQL wouldn’t use its spatial index (as I wrote before, although I > mistakenly wrote “spatial query” in my original email). > This would require some knowledge of the "metadata" of a function, which is not there in SQM at all so far. Here, I'd have to know the return type of the referenced function. We can contemplate that. https://hibernate.atlassian.net/browse/SQM-15