# Simple Design Question

**URL:** <https://forum.inductiveautomation.com/t/simple-design-question/3599>\
**Category:** Ignition\
**Created:** [November 14, 2011, 7:51pm UTC](https://forum.inductiveautomation.com/t/simple-design-question/3599 "2011-11-14T19:51:34Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![miketob](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/miketob/32/5936_2.png) [@miketob](https://forum.inductiveautomation.com/u/miketob)\
**Post date:** [November 14, 2011, 7:51pm UTC](https://forum.inductiveautomation.com/t/simple-design-question/3599/1 "2011-11-14T19:51:34Z")

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Hello,

I have a newbie question:

Whats the best way to keep the DB and a Tag in sync given this: I have a Set-point stored in the PLC and also in the database. I also have a Vision window where the user can change the value of the set-point. I also have the concern that if the PLC power supply fails I can lose the value of the set-point but if it’s stored on the DB it can be recovered. so, what should I do:

I have thought of these options

1. Bind a screen numeric input to the tag and add a script to update the DB
2. the numeric input stores the data in the DB and a SQLBridge transaction updates it to the PLC
3. the numeric input writes to the tag and a SQLBridge transaction updates the DB (but would this work when the PLC loses the set-point?)

Any guidance will be very appreciated

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**Author:** ![Travis.Cox](https://avatars.discourse-cdn.com/v4/letter/t/b9bd4f/32.png) [@Travis.Cox](https://forum.inductiveautomation.com/u/Travis.Cox)\
**Post date:** [November 14, 2011, 7:56pm UTC](https://forum.inductiveautomation.com/t/simple-design-question/3599/2 "2011-11-14T19:56:14Z")

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In this case it would be best to have a DB tag in a standard transaction group that is set to bi-directional OPC wins mapped to the right database table. Ignition will take care of synchronizing the two. You only need one group.

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**Author:** ![miketob](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/miketob/32/5936_2.png) [@miketob](https://forum.inductiveautomation.com/u/miketob)\
**Post date:** [November 14, 2011, 9:05pm UTC](https://forum.inductiveautomation.com/t/simple-design-question/3599/3 "2011-11-14T21:05:39Z")

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Thank you Travis,

And the numeric input would be binded to the DB tag?

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**Author:** ![Travis.Cox](https://avatars.discourse-cdn.com/v4/letter/t/b9bd4f/32.png) [@Travis.Cox](https://forum.inductiveautomation.com/u/Travis.Cox)\
**Post date:** [November 14, 2011, 9:59pm UTC](https://forum.inductiveautomation.com/t/simple-design-question/3599/4 "2011-11-14T21:59:59Z")

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Right 🙂

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**Author:** ![miketob](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/miketob/32/5936_2.png) [@miketob](https://forum.inductiveautomation.com/u/miketob)\
**Post date:** [November 15, 2011, 12:16am UTC](https://forum.inductiveautomation.com/t/simple-design-question/3599/5 "2011-11-15T00:16:19Z")

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Thank you Travis. It worked like a charm! ![:thumb_right:](https://us1.discourse-cdn.com/inductiveautomation/original/1X/2026e28c0c425034352c1b75807edf956adc75f4.gif ":thumb\_right:")