I noticed in standard transaction groups, one of the data types for a OPC/Group item is DataSet. How does one use this, seeing that I cannot create DataSet type SQL Tags? I have a window containing a table that displays the recipe currently assigned to a tank that is selected from a drop-down list. The recipe is obtained from a SQL query to Oracle. Rather than have each client (there could be dozens) re-query the database each time a different tank is chosen on the screen (and have to poll to know if another client has changed something on the recipe), we’d like to maintain the current recipe on the Gateway, using the same architecture/data flow used for individual OPC and DB SQLTags. Recipes can have varying amounts of instructions, so it’s difficult to maintain a static set of individual tags to represent this for each tank.
We currently have a stored procedure group for each tank that is used to retrieve, update, and increment through each individual step of the recipe. We would like to refresh the recipe display (they can and do change mid-batch when the lab adds instructions) each time the stored proc group posts an update to Oracle. It seems a bit wasteful and hurts scalability to have each client querying over and over when on distinct, known events it could be refreshed on the gateway. It appears the only types of SQLTags that can be DataSets are client tags, which cannot be used in transaction groups. I’m sure I could create client DataSet tags for each tank that only are updated when something changes on the Gateway, but I don’t know if this is an optimal solution either.
Assuming what I asked makes sense, does anyone have any suggestions?