diff --git a/src/main/java/org/caosdb/server/database/backend/implementation/MySQL/MySQLInsertFSODescriptor.java b/src/main/java/org/caosdb/server/database/backend/implementation/MySQL/MySQLInsertFSODescriptor.java
index c3f1cf34fb61e569483989753b17abc64b81b6f8..bfa02d1368dd08abdaf2a36b0da04b126d659766 100644
--- a/src/main/java/org/caosdb/server/database/backend/implementation/MySQL/MySQLInsertFSODescriptor.java
+++ b/src/main/java/org/caosdb/server/database/backend/implementation/MySQL/MySQLInsertFSODescriptor.java
@@ -41,9 +41,9 @@ public class MySQLInsertFSODescriptor extends MySQLTransaction implements Insert
         }
         insertFilePropsStmt.setString(6, entity.filePath.toString());
         if (entity.fileParentId != null) {
-          insertFilePropsStmt.setInt(7, entity.fileParentId);
+          insertFilePropsStmt.setString(7, entity.fileParentId);
         } else {
-          insertFilePropsStmt.setNull(7, Types.INTEGER);
+          insertFilePropsStmt.setNull(7, Types.VARCHAR);
         }
         if (entity.fileType == ObjectType.DIRECTORY) {
           insertFilePropsStmt.setString(8, "inode/directory");
diff --git a/src/main/java/org/caosdb/server/database/backend/implementation/MySQL/MySQLListFiles.java b/src/main/java/org/caosdb/server/database/backend/implementation/MySQL/MySQLListFiles.java
index 99b9ca8342a224d63b744cb7e48712856f814a56..cc087663d575149b2fc832f6c5e9cded78e554f7 100644
--- a/src/main/java/org/caosdb/server/database/backend/implementation/MySQL/MySQLListFiles.java
+++ b/src/main/java/org/caosdb/server/database/backend/implementation/MySQL/MySQLListFiles.java
@@ -30,11 +30,11 @@ class LiveFSODescriptor extends FSODescriptor {
       // resolve here and now
       children = new LinkedList<VirtualFSODescriptorInterface>();
       try {
-        pstmt.setInt(1, getEntityId().toInteger());
+        pstmt.setString(1, getEntityId().toString());
         try (ResultSet rs = pstmt.executeQuery()) {
           while (rs.next()) {
             final SparseEntity entity = new SparseEntity();
-            entity.id = rs.getInt("FileId");
+            entity.id = rs.getString("FileId");
             DatabaseUtils.parseFSODescriptorFields(rs, entity);
             children.add(new LiveFSODescriptor(entity, pstmt));
           }