Model Builder Append Tool Creating multiple features?

[RobertaDonaldson]

I am trying to append new data from one feature class to another (in a different geodatabase) using Model Builder. I am using the append tool and it works for most of the data but it duplicates almost all of it (theres over 2,000 features). How can I append new data from one to the other without duplicates all the features in the destination feature class?

Thanks!

[George_Thompson]

That seems to be the exact function of the tool, take the records from the source dataset and adding them into the target dataset; Append—Data Management toolbox | ArcGIS Desktop 

Are you just trying to update the attributes of the records or just add "new" records from the source that are not in the target?

[RobertaDonaldson]

I am trying to add the "new" records from the source that are not yet in the target. We continuously add to the source and at the end of each month we would like this tool to just append it all for us

[George_Thompson]

Ok, you could add a SQL expression (SQL reference for query expressions used in ArcGIS—ArcGIS Pro | ArcGIS Desktop) to the tool to bring over the "new" records only. You would just need a way to identify them in the source dataset.

[RobertaDonaldson]

Okay - How do I add this in? I don't have any experience with SQL expressions

[curtvprice]

I think a good way to try to select out matching records is to create a layer or table view (the Make Feature Layer or Make Table View tool) add a join by a key field with Add Join to your output dataset, select for otable.OBJECTID IS NULL (these are the no-matches), remove the join (Remove Join). Now you'll have a selected set of features that are not in your output dataset. Pass this as the source dataset to the append tool.

Another option (less complicated, but maybe too slow) is to go ahead and append them all and later use Delete Identical to clean up duplicate records at the end of the process. But make sure you save  a copy of the dataset you appending to around in case something goes wrong! Best not to tempt fate.

Hope this helps!