postgres.git / summary / log / commit / refs

commit    9e84cccff28e52ab76aa3d3e88bd815dc36d24d8
Author:   Bruce Momjian <bruce@momjian.us>
Date:     Wed Aug 15 03:21:13 2012 +0000

    Add doc example of restricting large object trigger firing to only
    updates of the column of interest.


 doc/src/sgml/lo.sgml | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/lo.sgml b/doc/src/sgml/lo.sgml
index 3d56ba3f70a..0c11fdc20aa 100644
--- a/doc/src/sgml/lo.sgml
+++ b/doc/src/sgml/lo.sgml
@@ -76,7 +76,15 @@ CREATE TRIGGER t_raster BEFORE UPDATE OR DELETE ON image
   <para>
    For each column that will contain unique references to large objects,
    create a <literal>BEFORE UPDATE OR DELETE</> trigger, and give the column
-   name as the sole trigger argument.  If you need multiple <type>lo</>
+   name as the sole trigger argument.  You can also restrict the trigger
+   to only execute on updates to the column with:
+
+<programlisting>
+CREATE TRIGGER t_raster BEFORE UPDATE OF raster OR DELETE ON image
+    FOR EACH ROW EXECUTE PROCEDURE lo_manage(raster);
+</programlisting>
+
+   If you need multiple <type>lo</>
    columns in the same table, create a separate trigger for each one,
    remembering to give a different name to each trigger on the same table.
   </para>


[parent: e45ae401811e]