docs: improve 'capitals' inheritance example

Bruce Momjian <bruce@momjian.us>

Commit: 4d93773798d68915b3b7d870bdceae9869b62f03
Author: Bruce Momjian <bruce@momjian.us>
Date: 2020-08-31T17:43:04Z
Releases: 9.6.20
docs:  improve 'capitals' inheritance example

Adds constraints and improves wording.

Reported-by: 2552891@gmail.com

Discussion: https://postgr.es/m/159586122762.680.1361378513036616007@wrigleys.postgresql.org

Backpatch-through: 9.5

Files

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doc/src/sgml/advanced.sgml modified +3 −2

Documentation touched