What would be the step by step walk-through for building a basic Entity-Relationship Diagram from pgAdmin?
Would there be some plugins for doing that in pgAdmin?
Note: I searched in the web but other than stumbling upon an exhausting list of softwares (most of them not freeware or out-of-date) I wind up here without a clue.
Note2: My request is not narrowed down to pgAdmin, let's say I can export my tables.
Sadly, the database designer is not released with the main release of pgAdmin after all. (At least the case for version 1.16 through 1.22.)
You need to use
./configureto enable it. By default, it's disabled.
There are too many bugs and rough edges and not enough people interested to work on it.
pgAdmin had a GSoC project in 2011, in the course of which Luis Ochoa designed the new database designer - which can also reverse engineer ER diagrams from existing dbs. Unfortunately it wasn't ready for release with pgAdmin 1.14 (the current version). But it's in the repository for version 1.16 that will probably accompany the release of PostgreSQL 9.2.
There are still some rough edges, but Luis Ochoa recently announced he is working on it.