opx-doc.patch

text/x-diff

Download

Patch

Same data as JSON: GET /api/v1/attachments/:id/patch the parsed metadata as JSON — format, series position, per-file stats; never the diff bytes. API reference →

Format: unified

File	+	−
doc/src/sgml/ref/create_table.sgml	54	2

diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 082dfe4..a73c015 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -51,10 +51,13 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE <replaceable class="PAR
   PRIMARY KEY ( <replaceable class="PARAMETER">column_name</replaceable> [, ... ] ) <replaceable class="PARAMETER">index_parameters</replaceable> |
   CHECK ( <replaceable class="PARAMETER">expression</replaceable> ) |
   FOREIGN KEY ( <replaceable class="PARAMETER">column_name</replaceable> [, ... ] ) REFERENCES <replaceable class="PARAMETER">reftable</replaceable> [ ( <replaceable class="PARAMETER">refcolumn</replaceable> [, ... ] ) ]
-    [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE <replaceable class="parameter">action</replaceable> ] [ ON UPDATE <replaceable class="parameter">action</replaceable> ] }
+    [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE <replaceable class="parameter">action</replaceable> ] [ ON UPDATE <replaceable class="parameter">action</replaceable> ] |
+  EXCLUDE [ USING <replaceable class="parameter">index_method</replaceable> ]
+    ( { <replaceable class="parameter">column</replaceable> | <replaceable class="parameter">column</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] WITH <replaceable class="parameter">operator</replaceable> [, ... ] )
+    <replaceable class="parameter">index_parameters</replaceable> [ WHERE ( <replaceable class="parameter">predicate</replaceable> ) ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
 
-<phrase><replaceable class="PARAMETER">index_parameters</replaceable> in <literal>UNIQUE</literal> and <literal>PRIMARY KEY</literal> constraints are:</phrase>
+<phrase><replaceable class="PARAMETER">index_parameters</replaceable> in <literal>UNIQUE</literal>, <literal>PRIMARY KEY</literal>, and <literal>EXCLUDE</literal> constraints are:</phrase>
 
 [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> [= <replaceable class="PARAMETER">value</replaceable>] [, ... ] ) ]
 [ USING INDEX TABLESPACE <replaceable class="PARAMETER">tablespace</replaceable> ]
@@ -547,6 +550,43 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE <replaceable class="PAR
    </varlistentry>
 
    <varlistentry>
+    <term><literal>EXCLUDE [ USING <replaceable class="parameter">index_method</replaceable> ]
+      ( {<replaceable class="parameter">column</replaceable> | <replaceable class="parameter">column</replaceable> | (<replaceable class="parameter">expression</replaceable> ) } [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] WITH <replaceable class="parameter">operator</replaceable> [, ... ] )
+      <replaceable class="parameter">index_parameters</replaceable> [ WHERE ( <replaceable class="parameter">predicate</replaceable> ) ] }</literal></term>
+    <listitem>
+     <para>
+      The <literal>EXCLUDE</> clause specifies an operator exclusion
+      constraint.  An operator exclusion constraint guarantees that if any two
+      tuples are compared on the specified columns or expressions using the
+      specified operators, at least one such comparison will return false.
+      If all of the specified operators test for equality, it is equivalent
+      to a UNIQUE constraint, although an ordinary unique constraint will
+      normally be faster.  However, operator exclusion constraints can use
+      index methods other than btree, and can specify more general constraints.
+      For instance, you can specify the constraint that no two tuples in the
+      table contain overlapping circles
+      (see <xref linkend="datatype-geometric">) by using the
+      <literal>&&</literal> operator.
+     </para>
+
+     <para>
+      Operator exclusion constraints are implemented internally using
+      an index, so the specified operators must be associated with an
+      appropriate operator class for the given access method, and the
+      access method must support amgettuple (see <xref linkend="indexam">
+      for details).  The operators are also required to be their own
+      commutators (see <xref linkend="sql-createoperator">).
+     </para>
+
+     <para>
+      The <replaceable class="parameter">predicate</replaceable>
+      allows you to specify a constraint on a subset of the table,
+      internally using a partial index.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><literal>DEFERRABLE</literal></term>
     <term><literal>NOT DEFERRABLE</literal></term>
     <listitem>
@@ -1111,6 +1151,18 @@ CREATE TABLE cinemas (
 </programlisting>
   </para>
 
+  <para>
+   Create table <structname>circles</> with an operator exclusion
+   constraint that prevents overlapping circles within it:
+
+<programlisting>
+CREATE TABLE circles (
+	c circle,
+	EXCLUDE USING gist (c WITH &&)
+);
+</programlisting>
+  </para>
+
  </refsect1>
 
  <refsect1 id="SQL-CREATETABLE-compatibility">