Support CREATE SCHEMA IF NOT EXISTS.

Per discussion, schema-element subcommands are not allowed together with
this option, since it's not very obvious what should happen to the element
objects.

Fabrízio de Royes Mello

1 files changed, 27 insertions, 0 deletions

diff --git a/doc/src/sgml/ref/create_schema.sgml b/doc/src/sgml/ref/create_schema.sgml
index 930d876814d..2602bb1d56f 100644
--- a/doc/src/sgml/ref/create_schema.sgml
+++ b/doc/src/sgml/ref/create_schema.sgml
@@ -23,6 +23,8 @@ PostgreSQL documentation
 <synopsis>
 CREATE SCHEMA <replaceable class="parameter">schema_name</replaceable> [ AUTHORIZATION <replaceable class="parameter">user_name</replaceable> ] [ <replaceable class="parameter">schema_element</replaceable> [ ... ] ]
 CREATE SCHEMA AUTHORIZATION <replaceable class="parameter">user_name</replaceable> [ <replaceable class="parameter">schema_element</replaceable> [ ... ] ]
+CREATE SCHEMA IF NOT EXISTS <replaceable class="parameter">schema_name</replaceable> [ AUTHORIZATION <replaceable class="parameter">user_name</replaceable> ]
+CREATE SCHEMA IF NOT EXISTS AUTHORIZATION <replaceable class="parameter">user_name</replaceable>
 </synopsis>
  </refsynopsisdiv>
 
@@ -98,6 +100,17 @@ CREATE SCHEMA AUTHORIZATION <replaceable class="parameter">user_name</replaceabl
        </para>
       </listitem>
      </varlistentry>
+
+     <varlistentry>
+      <term><literal>IF NOT EXISTS</literal></term>
+      <listitem>
+       <para>
+        Do nothing (except issuing a notice) if a schema with the same name
+        already exists.  <replaceable class="parameter">schema_element</>
+        subcommands cannot be included when this option is used.
+       </para>
+      </listitem>
+     </varlistentry>
     </variablelist>
  </refsect1>
 
@@ -130,6 +143,15 @@ CREATE SCHEMA AUTHORIZATION joe;
   </para>
 
   <para>
+   Create a schema named <literal>test</> that will be owned by user
+   <literal>joe</>, unless there already is a schema named <literal>test</>.
+   (It does not matter whether <literal>joe</> owns the pre-existing schema.)
+<programlisting>
+CREATE SCHEMA IF NOT EXISTS test AUTHORIZATION joe;
+</programlisting>
+  </para>
+
+  <para>
    Create a schema and create a table and view within it:
 <programlisting>
 CREATE SCHEMA hollywood
@@ -177,6 +199,11 @@ CREATE VIEW hollywood.winners AS
    schema owner.  This can happen only if the schema owner grants the
    <literal>CREATE</> privilege on his schema to someone else.
   </para>
+
+  <para>
+   The <literal>IF NOT EXISTS</literal> option is a
+   <productname>PostgreSQL</productname> extension.
+  </para>
  </refsect1>
 
  <refsect1>