fix autoincrement column introspection in DB2

lib/Doctrine/DBAL/Platforms/DB2Platform.php

@@ -273,7 +273,11 @@ class DB2Platform extends AbstractPlatform
     {
         return "SELECT DISTINCT c.tabschema, c.tabname, c.colname, c.colno,
                 c.typename, c.default, c.nulls, c.length, c.scale,
-                c.identity, tc.type AS tabconsttype, k.colseq
+                c.identity, tc.type AS tabconsttype, k.colseq,
+                CASE
+                    WHEN c.generated = 'D' THEN 1
+                    ELSE 0
+                END AS autoincrement
                 FROM syscat.columns c
                 LEFT JOIN (syscat.keycoluse k JOIN syscat.tabconst tc
                 ON (k.tabschema = tc.tabschema

lib/Doctrine/DBAL/Schema/DB2SchemaManager.php

@@ -93,6 +93,7 @@ class DB2SchemaManager extends AbstractSchemaManager
             'unsigned'      => (bool)$unsigned,
             'fixed'         => (bool)$fixed,
             'default'       => $default,
+            'autoincrement' => (boolean) $tableColumn['autoincrement'],
             'notnull'       => (bool) ($tableColumn['nulls'] == 'N'),
             'scale'         => null,
             'precision'     => null,