fixed db import transactions

modules/system/databaseMigration.py

@@ -743,15 +743,15 @@ def _importSingleDb(payload: dict, dbName: str, mode: str, protectedIds: List[st
     conn = _getConnection(dbName)
     try:
         existingTables = set(_listTables(conn))
+        conn.rollback()
 
         # Ensure all import tables exist (create missing ones from export schema)
+        conn.autocommit = True
         for tableName, rows in tables.items():
             if tableName in excluded or not isinstance(rows, list) or not rows:
                 continue
             if tableName not in existingTables:
-                conn.autocommit = True
                 _createTableFromExport(conn, tableName, rows)
-                conn.autocommit = False
                 existingTables.add(tableName)
                 logger.info("Pre-created missing table %s.%s", dbName, tableName)
 
@@ -770,9 +770,9 @@ def _importSingleDb(payload: dict, dbName: str, mode: str, protectedIds: List[st
 
         # Phase 1 (replace only): DELETE children first (reverse topological order)
         if mode == "replace":
+            conn.autocommit = False
             for tableName in reversed(importOrder):
                 try:
-                    conn.autocommit = False
                     _deleteNonProtected(conn, tableName, protectedIdSet)
                     conn.commit()
                 except Exception as e:
@@ -781,12 +781,13 @@ def _importSingleDb(payload: dict, dbName: str, mode: str, protectedIds: List[st
                     logger.warning("DELETE from %s.%s failed: %s", dbName, tableName, e)
 
         # Phase 2: INSERT parents first (topological order)
+        conn.autocommit = False
         for tableName in importOrder:
             try:
-                conn.autocommit = False
                 rows = tables[tableName]
                 physicalCols = _getPhysicalColumns(conn, tableName)
                 if not physicalCols:
+                    conn.rollback()
                     continue
 
                 filteredRows = []