Logical schema diagrams are (or were) written for the following versions:

• 3.0.3 by Matteo Romanello. It is a work done with the sofware SchemaSpy. There are two packages:
  1. The first has only the Koha logical schema. This zip files is 9,9 MB.
  2. The second has Koha logical schema and also the instructions to update documentation. This zip file is 10,2 MB.

• 3.0.1 by Joe a partial 3.0.1 diagram as PNG image.

• 3.0 by Paul. It's a 2 page document. You can see the general overview of Koha DB. Available in some forms: openoffice.org (15KB), PDF (287 KB) It will be updated when needed (Paul will take care of the update. If he don't, bug him)

• 2.2.0 by Paul. It's a 2 page document. ZIP file (100 KB)

• 2.0.0 by Paul. It's a 2 page document. ZIP file (150 KB)

• Some draft 'logical' schema diagrams from 1.3.3 are [http://irref.mine.nu/user/dchud/koha-schema/ available here]

Note that some of these links need to be updated.