Added check for SELECT with LIMIT...this won't fly with SQLBase.

sqlbase7_sa/base.py

@@ -29,6 +29,16 @@ from sqlalchemy.sql.compiler import SQLCompiler
 from sqlalchemy.sql.expression import Join
 
 
+class LimitClauseNotSupported(Exception):
+
+    def __init__(self, limit, offset):
+        self.limit = limit
+        self.offset = offset
+
+    def __str__(self):
+        return "Centura SQLBase 7.5.1 doesn't support a LIMIT clause for the SELECT statement (received: limit = %u, offset = %u)" % (self.limit, self.offset)
+
+
 class SQLBase7Compiler(SQLCompiler):
 
     # Most of the code below was copied from the Oracle dialect.  Thanks to Michael Bayer
@@ -41,9 +51,12 @@ class SQLBase7Compiler(SQLCompiler):
     def visit_select(self, select, **kwargs):
         froms = select._get_display_froms()
         whereclause = self._get_join_whereclause(froms)
-        if whereclause:
+        if whereclause is not None:
             select = select.where(whereclause)
 
+        if select._limit is not None or select._offset is not None:
+            raise LimitClauseNotSupported(select._limit, select._offset)
+
         kwargs['iswrapper'] = getattr(select, '_is_wrapper', False)
         return SQLCompiler.visit_select(self, select, **kwargs)