diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/create_domain.sgml | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/doc/src/sgml/ref/create_domain.sgml b/doc/src/sgml/ref/create_domain.sgml index 73f9f28d6cf..ce555203486 100644 --- a/doc/src/sgml/ref/create_domain.sgml +++ b/doc/src/sgml/ref/create_domain.sgml @@ -24,9 +24,9 @@ PostgreSQL documentation CREATE DOMAIN <replaceable class="parameter">name</replaceable> [ AS ] <replaceable class="parameter">data_type</replaceable> [ COLLATE <replaceable>collation</replaceable> ] [ DEFAULT <replaceable>expression</replaceable> ] - [ <replaceable class="parameter">constraint</replaceable> [ ... ] ] + [ <replaceable class="parameter">domain_constraint</replaceable> [ ... ] ] -<phrase>where <replaceable class="parameter">constraint</replaceable> is:</phrase> +<phrase>where <replaceable class="parameter">domain_constraint</replaceable> is:</phrase> [ CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> ] { NOT NULL | NULL | CHECK (<replaceable class="parameter">expression</replaceable>) } @@ -190,7 +190,7 @@ CREATE DOMAIN <replaceable class="parameter">name</replaceable> [ AS ] <replacea </variablelist> </refsect1> - <refsect1> + <refsect1 id="sql-createdomain-notes"> <title>Notes</title> <para> @@ -279,6 +279,17 @@ CREATE TABLE us_snail_addy ( The command <command>CREATE DOMAIN</command> conforms to the SQL standard. </para> + + <para> + The syntax <literal>NOT NULL</literal> in this command is a + <productname>PostgreSQL</productname> extension. (A standard-conforming + way to write the same would be <literal>CHECK (VALUE IS NOT + NULL)</literal>. However, per <xref linkend="sql-createdomain-notes"/>, + such constraints are best avoided in practice anyway.) The + <literal>NULL</literal> <quote>constraint</quote> is a + <productname>PostgreSQL</productname> extension (see also <xref + linkend="sql-createtable-compatibility"/>). + </para> </refsect1> <refsect1 id="sql-createdomain-see-also"> |