Data relationship comparison

When comparing data relationship options in ArcGIS Pro, they can seem similar, though they each have their benefits, limitations, and reasons you might consider using each one.

If needed, see Data relationship options before comparing and deciding which data relationship option to use.

The following summary highlights reasons you might consider using each of these data relationship options in ArcGIS Pro.

• Relationship classes—Relationship classes in ArcGIS Pro are useful for maintaining the referential integrity of related data. Relationship classes enable the navigation of complex relationships between different types of data, simplifying data management and analysis. This means if the primary feature is deleted or modified in the origin table, the corresponding related features in the destination table can be automatically deleted or modified, which helps to maintain the accuracy, consistency, and integrity of the data in your geodatabase. Furthermore, a relationship class is stored, persists as a dataset type in the geodatabase, and can be accessed by all users with geodatabase access.

• Relates—Relates are a useful feature in ArcGIS Pro for finding and selecting features in related layers or tables, particularly during editing workflows. They can enhance editing performance by allowing you to access and analyze related attribute data. Relates are defined as a property of a layer in ArcGIS Pro and provide a convenient way to work with related data.

• Joins—Joins in ArcGIS Pro are useful because they allow you to combine data from different tables or layers based on a common attribute. Joins allow you to access and display related attribute data, perform spatial analysis using combined attributes, and create more comprehensive maps and visualizations. Joins are particularly beneficial for labeling and symbology purposes, as they help integrate multiple sources of information and provide a more holistic understanding of your data.

Decide which data relationship option to use

The following table provides a detailed comparison of these three nonspatial data relationship options.

Relationship classes, relates, and joins

	Relationship classes	Relates	Joins
How to create	Create Relationship Class	Add Relate	Add Join
Supported data types	Feature class or table	Feature layers, table views, subtype group layers, and raster layers with a raster attribute table	Feature layers, table views, or a raster layer with an attribute table
Lifespan	Persists	Temporary	Temporary
Participating data location	Both objects must reside in the same geodatabase.	Any two compatible objects	Any two compatible objects
Stored In	Geodatabase	Project or layer	Project or layer
Cardinality	One-to-one One-to-many Many-to-many	One-to-one One-to-many Many-to-many	One-to-one Many-to-one See Additional notes for more details.
User interface for editing	ArcGIS Pro	ArcGIS Pro	SQL queries
User interface for navigating	ArcGIS Pro	ArcGIS Pro	SQL queries
Composite objects	Yes	No	No
Referential integrity	Yes	No	No
Messaging	Yes	No	No
Attributes	Yes	No	No
Relationship rules	Yes	No	No
Typical uses	Ensuring data integrity	Editing with low overhead	Labeling, symbology
Benefits	Supports query, editing, referential integrity, attributed relationships, and relationship rules.	Creating relates between multiple tables, allows you to query related tables in different formats. There is no editing overhead, and it can cross workspace and data source type.	Creates a single virtual table from two tables. There is no editing overhead, and it can cross workspace and data source type. Use the additional attribute information in SQL queries, labeling, and symbology.
Limitations	Incurs editing overhead. It must be defined only between tables in same geodatabase within the same user schema, and it still requires joins for SQL query, labeling, and symbology.	Relates do not modify data; they are a property of the layer. There is no referential integrity and no messaging. It still requires joins for SQL query, labeling, and symbology.	Joins will always reside in the layer, not with the data. There is no referential integrity, no messaging, and no support for many-to-many relationships. One-to-many relationships involving feature classes are not supported.
Additional notes		To save the relate for use in another project, save the layer to a layer file using the Save Layer To File tool. This only applies to layers; table views cannot be saved in this manner. To make a permanent relate, use the Create Relationship Class tool.	You can create a join under the circumstances where a one-to-many or many-to-many relationship exists; however, there are differences between how tools and other layer-specific settings work depending on the data source. If you are using data in the same geodatabase to create the join, Keep all input records is set by default. If you are using nondatabase data, such as shapefiles or dBASE tables, to create the join, only the first matching record is returned. The join persists only for the duration of the layer. A layer can be retained by saving the ArcGIS Pro session or by saving it to a layer file using the Save Layer To File tool. To make a permanent join, either use the Join Field tool or use the joined layer as input to one of the following tools: Copy Features, Copy Rows, Export Features, or Export Table.

To learn more about relationship classes, see Geodatabase relationship class types.