How do I load saved relates in ModelBuilder?

[MarjorieSinclair]

I'm trying to automate extracting data from a geodatabase using ModelBuilder (ArcMap 10.3). I have a set of saved relates and can't find how to connect them.

[curtvprice]

I don't know what you mean by a saved relate. The only way you can save a relate is to save a layer file with a relate set up. Are you talking about geodatabase relationship classes? The only way to set them up in a new copy of a geodatabase is to recreate them using the Create Relationship Class tool.

[MarjorieSinclair]

I have a better grasp of the vocabulary today than I did 6 weeks ago.
I have a geodatabase containing shapefiles and relationship classes. Within ArcMap, I load the saved relationship classes and extract related data. I'm trying to automate the process in Model Builder (or Python) and can't find a tutorial on how to use a relationship class once it's been created.

[curtvprice]

Relationship classes are really more for interactive use while editing and working with tables, though they can enforce referential integrity when modifying data using MB or scripting. Here's a little tutorial on how they are used in the help:

Exploring the related objects of an object in a table—Help | ArcGIS Desktop 

In scripting and MB you need to do your select-by-joining operations using Add Join (or if you are into that (Dan Patterson‌) using Python dictionaries. Relationship classes are not accessible for use through geoprocessing (as far as I know).

[DanPatterson_Retired]

Curtis... Richard Fairhurst‌ is the dictionary goto... Turbo-charging data manipulation with python cursors and dictionaries

[DuncanHornby]

You should check out this blog for relate like operations in model builder.