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
This commit is contained in:
Bruce Momjian 2020-08-31 13:43:04 -04:00
parent 785affc1d6
commit 64fd65008c

View File

@ -616,7 +616,7 @@ CREATE TABLE cities (
);
CREATE TABLE capitals (
state char(2)
state char(2) UNIQUE NOT NULL
) INHERITS (cities);
</programlisting>
</para>
@ -630,7 +630,8 @@ CREATE TABLE capitals (
<type>text</type>, a native <productname>PostgreSQL</productname>
type for variable length character strings. The
<classname>capitals</classname> table has
an extra column, <structfield>state</structfield>, which shows their states. In
an additional column, <structfield>state</structfield>, which shows its
state abbreviation. In
<productname>PostgreSQL</productname>, a table can inherit from
zero or more other tables.
</para>