doc: Clarify CREATE TYPE ENUM documentation

petere · petere · commit 69bae2372725 · 2018-11-20T09:37:02.000+01:00
The documentation claimed that an enum type requires "one or more" labels, but since 1fd9883, zero labels are also allowed. Reported-by: Lukas Eder <lukas.eder@gmail.com> Bug: #15356
diff --git a/doc/src/sgml/ref/create_type.sgml b/doc/src/sgml/ref/create_type.sgml
@@ -117,9 +117,12 @@ CREATE TYPE <replaceable class="parameter">name</replaceable>
    <para>
     The second form of <command>CREATE TYPE</command> creates an enumerated
     (enum) type, as described in <xref linkend="datatype-enum"/>.
-    Enum types take a list of one or more quoted labels, each of which
+    Enum types take a list of quoted labels, each of which
     must be less than <symbol>NAMEDATALEN</symbol> bytes long (64 bytes in a
-    standard <productname>PostgreSQL</productname> build).
+    standard <productname>PostgreSQL</productname> build).  (It is possible to
+    create an enumerated type with zero labels, but such a type cannot be used
+    to hold values before at least one label is added using <xref
+    linkend="sql-altertype"/>.)
    </para>
   </refsect2>
 
