diff --git a/symmetric-assemble/src/docbook/configuration.xml b/symmetric-assemble/src/docbook/configuration.xml
index 39fbdee7f3..00599b9fec 100644
--- a/symmetric-assemble/src/docbook/configuration.xml
+++ b/symmetric-assemble/src/docbook/configuration.xml
@@ -1191,11 +1191,35 @@ router_expression, create_time, last_update_time) values
'EXTERNAL_DATA=:EXTERNAL_ID', current_timestamp, current_timestamp);
-Note the syntax $(curTriggerValue).$(curColumnPrefix). This
-translates into "OLD_" or "NEW_" based on the DML type being run. In the
-case of Insert or Update, it's NEW_. For Delete, it's OLD_ (since there
-is no new data). In this way, you can access the DML-appropriate value
-for your select statement.
+The following variables can be used with the external select:
+
+
+
+
+ $(curTriggerValue)
+
+
+
+ Variable to be replaced with the NEW or OLD column alias provided by the trigger context, which is platform specific.
+ For insert and update triggers, the NEW alias is used; for delete triggers, the OLD alias is used.
+ For example, "$(curTriggerValue).COLUMN" becomes ":new.COLUMN" for an insert trigger on Oracle.
+
+
+
+
+
+
+ $(curColumnPrefix)
+
+
+
+ Variable to be replaced with the NEW_ or OLD_ column prefix for platforms that don't support column aliases.
+ This is currently only used by the H2 database. All other platforms will replace the variable with an empty string.
+ For example "$(curColumnPrefix)COLUMN" becomes "NEW_COLUMN" on H2 and "COLUMN" on Oracle.
+
+
+
+
The advantage of this approach over the 'subselect'
approach is that it guards against the (somewhat unlikely) possibility