- changed "for_update" parameter to accept False/True/"nowait"

and "read", the latter two of which are interpreted only by
Oracle and Mysql [ticket:292]
- added "lockmode" argument to base Query select/get functions,
including "with_lockmode" function to get a Query copy that has
a default locking mode.  Will translate "read"/"update"
arguments into a for_update argument on the select side.
[ticket:292]

2 files changed, 12 insertions, 0 deletions

diff --git a/lib/sqlalchemy/databases/mysql.py b/lib/sqlalchemy/databases/mysql.py
index c6d78cf90..4eab9e55c 100644
--- a/lib/sqlalchemy/databases/mysql.py
+++ b/lib/sqlalchemy/databases/mysql.py
@@ -411,6 +411,12 @@ class MySQLCompiler(ansisql.ANSICompiler):
             # TODO: put whatever MySQL does for CAST here.
             self.strings[cast] = self.strings[cast.clause]
 
+    def for_update_clause(self, select):
+        if select.for_update == 'read':
+             return ' LOCK IN SHARE MODE'
+        else:
+            return super(MySQLCompiler, self).for_update_clause(select)
+
     def limit_clause(self, select):
         text = ""
         if select.limit is not None:
diff --git a/lib/sqlalchemy/databases/oracle.py b/lib/sqlalchemy/databases/oracle.py
index 5f574338b..5db157cbb 100644
--- a/lib/sqlalchemy/databases/oracle.py
+++ b/lib/sqlalchemy/databases/oracle.py
@@ -402,6 +402,12 @@ class OracleCompiler(ansisql.ANSICompiler):
     def limit_clause(self, select):
         return ""
 
+    def for_update_clause(self, select):
+        if select.for_update=="nowait":
+            return " FOR UPDATE NOWAIT"
+        else:
+            return super(OracleCompiler, self).for_update_clause(select)
+
 class OracleSchemaGenerator(ansisql.ANSISchemaGenerator):
     def get_column_specification(self, column, **kwargs):
         colspec = self.preparer.format_column(column)