Add MySQL support for safe_add_column.

1 files changed, 13 insertions, 8 deletions

diff --git a/askbot/migrations_api/__init__.py b/askbot/migrations_api/__init__.py
index 0260f51b..3ea250f2 100644
--- a/askbot/migrations_api/__init__.py
+++ b/askbot/migrations_api/__init__.py
@@ -13,14 +13,19 @@ def safe_add_column(table, column, column_data, keep_default = False):
     so, we need to add these columns here in separate transactions
     and roll back if they fail, if we want we could also record - which columns clash
     """
-    try:
-        db.start_transaction()
-        db.add_column(table, column, column_data, keep_default = keep_default)
-        db.commit_transaction()
-        return True
-    except:
-        db.rollback_transaction()
-        return False
+    if db.backend_name=='mysql':
+        if len(db.execute('select column_name from information_schema.columns where table_name=%s and column_name=%s', params=[table, column])) == 0:
+            db.add_column(table, column, column_data, keep_default = keep_default)
+    	
+    else:
+        try:
+            db.start_transaction()
+            db.add_column(table, column, column_data, keep_default = keep_default)
+            db.commit_transaction()
+            return True
+	except:
+	    db.rollback_transaction()
+            return False
 
 
 def mysql_table_supports_full_text_search(table_name):