Developing rails websites with a geographic component we rely heavily on Postgis, so we use activerecord-postgis-adapter for the Postgis support, and I always use schema_plus because it allows me to define views. Until recently, I always had to use the structure.sql instead of the schema.rb because the geometric columns did not dump correctly.

But for a while now, activerecord-postgis-adapter handles this correctly and so we use the schema.rb file again. Only to discover a “new” error:

ActiveRecord::StatementInvalid: PG::DependentObjectsStillExist: ERROR:  cannot drop view geography_columns because extension postgis requires it
HINT:  You can drop extension postgis instead.
: DROP VIEW IF EXISTS "geography_columns"

Apparently specific Postgis views are also dumped in the schema file, and those views obviously cannot simply be re-created.

A very naive solution I kept using was to comment those create_view lines in our schema.rb file. But apparently there is a much better solution: you can configure which tables and views schema_plus should ignore.

So I added an initializer in /initializers/schema_dumper.rb with the following content:

ActiveRecord::SchemaDumper.ignore_tables = [
   "geography_columns", "geometry_columns", "spatial_ref_sys", "raster_columns", "raster_overviews"

And now my schema.rb is correct, and simple commands as rake db:setup or rake db:test:prepare just work. Hehe.