diff --git a/lib/plsql/jdbc_connection.rb b/lib/plsql/jdbc_connection.rb
index 8f06920..3b9e127 100644
--- a/lib/plsql/jdbc_connection.rb
+++ b/lib/plsql/jdbc_connection.rb
@@ -223,8 +223,6 @@ def prepare_call(sql, *bindvars)
     end
 
     RUBY_CLASS_TO_SQL_TYPE = {
-      Fixnum => java.sql.Types::INTEGER,
-      Bignum => java.sql.Types::INTEGER,
       Integer => java.sql.Types::INTEGER,
       Float => java.sql.Types::FLOAT,
       BigDecimal => java.sql.Types::NUMERIC,