# Transaction Group \_ndx Question **URL:** \ **Category:** Ignition\ **Created:** [October 3, 2023, 3:50pm UTC](https://forum.inductiveautomation.com/t/transaction-group-ndx-question/79985 "2023-10-03T15:50:03Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![McAlisterD](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@McAlisterD](https://forum.inductiveautomation.com/u/McAlisterD)\ **Post date:** [October 3, 2023, 3:50pm UTC](https://forum.inductiveautomation.com/t/transaction-group-ndx-question/79985/1 "2023-10-03T15:50:03Z")
I created a Transaction Group to store cycle data to a table. My customer is querying this table to transfer the data to his system. He uses the \_ndx column to detect new data. We are seeing this column reset to a lower number sometimes. It remains unique but is not always higher than a previous record. How does the TG generate the \_ndx data? ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [October 3, 2023, 3:52pm UTC](https://forum.inductiveautomation.com/t/transaction-group-ndx-question/79985/2 "2023-10-03T15:52:10Z")
It's usually the database engine that does that automatically. (The INSERT query normally doesn't pass any data to that column.) What engine are you using? ---
**Author:** ![McAlisterD](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@McAlisterD](https://forum.inductiveautomation.com/u/McAlisterD)\ **Post date:** [October 3, 2023, 3:52pm UTC](https://forum.inductiveautomation.com/t/transaction-group-ndx-question/79985/3 "2023-10-03T15:52:37Z")
MySQL