I'm currently using PostGIS 1.5.3, but I will be upgrading to 2.0 soon. So please note any differences between the two versions that are relevant to the following questions.
- Is it possible to create a column of the PostGIS geometry type that allows insertion of polygons and multipolygons but restricts insertion of other geometry types without manually modifying the constraint PostGIS generates when calling AddGeometryColumn?
- Are there reasons not to do this? In particular, does PostGIS store any metadata that manually modifying the constraint might negatively impact? (I'm very new to PostGIS, so forgive me if the idea of PostGIS storing metadata is absurd.)
- How significant is any overhead incurred by using multipolygons for everything?
I'm already aware of using ST_Multi to convert polygons into multipolygons before insertion, so if it's not possible or not a good idea, I'll do that.