On Thu, May 15, 2014 at 12:21 PM, Brian Duggan <bduggan@usgcrp.gov> wrote:
>
> Postgres has some nice features like the hstore datatype which allow the
> relational data model to be pushed a bit to accomodate more
> expressive semantic relationships.
Note:
hstore is an additional supplied module, so it needs to be enabled for
each database you want to use it with; make sure to install contrib, and
run 'CREATE EXTENSION hstore'.
Also note that, all values are stored as text, and only one value is stored
per key; this can be worked around, but makes indexing multi-valued
properties a bit complicated. There is a function for mapping to json
that attempts to remove quotes from reals and integers.
Another issue to watch for is that changing any value creates a new row
version, which can be costly in terms of indexing, and can also reduce the
effectiveness of index-only scans (there must be an invisible row).
Simon
Received on Thursday, 15 May 2014 22:54:09 UTC