Add Attributes from Another Case Table Using Table Join

How To... > Work with Case Tables > Add Attributes from Another Case Table Using Table Join

Suppose you have two collections of data about your class, and you want to graph attributes from them both on the same graph. If both collections have an attribute that uniquely identifies each student in the class, you can easily bring the missing attributes from one collection into another. The cases don’t have to be in the same order in the two collections. Fathom uses the "key" attributes to match cases properly. This matching operation is called a table join.

1.	Put both collections in the same document, each with its own case table. (Copy the collection from one document, and paste it into the document you want to add to. Make case tables for both collections; see Make a New Case Table.)

2.	Drag the name of the key attribute from the source collection, and drop it on the name of the key attribute in the destination collection. (Below, student is dropped on name.)

_img91

_img14

Fathom adds any attributes in the source collection that are missing from the destination to the attributes in the destination collection. The added attribute(s) have formulas using the Lookup function (see lookupValueByKey). If you want to delete the source collection, you first need to clear the formulas (otherwise, the data you’ve just brought over will be lost).