- FOR UPDATE is emitted in the syntactically correct position

when limit/offset is used, i.e. the ROWNUM subquery.
However, Oracle can't really handle FOR UPDATE with ORDER BY
or with subqueries, so its still not very usable, but at
least SQLA gets the SQL past the Oracle parser.
[ticket:1815]

1 files changed, 14 insertions, 10 deletions

diff --git a/lib/sqlalchemy/dialects/oracle/base.py b/lib/sqlalchemy/dialects/oracle/base.py
index 6c8055138..cd232fa00 100644
--- a/lib/sqlalchemy/dialects/oracle/base.py
+++ b/lib/sqlalchemy/dialects/oracle/base.py
@@ -479,7 +479,7 @@ class OracleCompiler(compiler.SQLCompiler):
 
                 limitselect._oracle_visit = True
                 limitselect._is_wrapper = True
-
+                
                 # If needed, add the limiting clause
                 if select._limit is not None:
                     max_row = select._limit
@@ -490,22 +490,24 @@ class OracleCompiler(compiler.SQLCompiler):
 
                 # If needed, add the ora_rn, and wrap again with offset.
                 if select._offset is None:
+                    limitselect.for_update = select.for_update
                     select = limitselect
                 else:
-                     limitselect = limitselect.column(
+                    limitselect = limitselect.column(
                              sql.literal_column("ROWNUM").label("ora_rn"))
-                     limitselect._oracle_visit = True
-                     limitselect._is_wrapper = True
+                    limitselect._oracle_visit = True
+                    limitselect._is_wrapper = True
 
-                     offsetselect = sql.select(
+                    offsetselect = sql.select(
                              [c for c in limitselect.c if c.key!='ora_rn'])
-                     offsetselect._oracle_visit = True
-                     offsetselect._is_wrapper = True
+                    offsetselect._oracle_visit = True
+                    offsetselect._is_wrapper = True
 
-                     offsetselect.append_whereclause(
+                    offsetselect.append_whereclause(
                              sql.literal_column("ora_rn")>select._offset)
 
-                     select = offsetselect
+                    offsetselect.for_update = select.for_update
+                    select = offsetselect
 
         kwargs['iswrapper'] = getattr(select, '_is_wrapper', False)
         return compiler.SQLCompiler.visit_select(self, select, **kwargs)
@@ -514,7 +516,9 @@ class OracleCompiler(compiler.SQLCompiler):
         return ""
 
     def for_update_clause(self, select):
-        if select.for_update == "nowait":
+        if self.is_subquery():
+            return ""
+        elif select.for_update == "nowait":
             return " FOR UPDATE NOWAIT"
         else:
             return super(OracleCompiler, self).for_update_clause(select)