Relating shapefile to excel table in ArcMap?

Question

I have successfully joined a point shapefile to .CSV file in ArcMap 10.0, and the type of the fields which are related in the two files are the same(text, length:255). But when I remove join and relate the two files, open the attribute table of the shapefile, and click the "Related Table" button, the option is greyed out... How can I solve this problem?

Answer 1

The help for ArcGIS is clear that you cannot do relates with Excel documents or any other document that does not support an ObjectID in the Fundamentals of ObjectID fields help.

This help clearly states:

"If your table lacks an ObjectID field, you won't be able to perform the following operations:

• Select the features in the layer on the map. Although you can select records in the Table window, including selecting using an expression on Select By Attributes, this selection set is not reflected on the map.
• Apply a definition query to display only a subset of records or features.
• Create relates. You can relate to a table without an ObjectID field from a table with an ObjectID field, however. In this case, the relate can be used by the Identify tool to list related records. You can't push selections via the relate.
• Start an edit session and edit the attributes. However, you can edit the table the layer is based on directly on disk, such as in a text editor if the file is a .txt file. Your changes will then be reflected on the map the next time you refresh the map."

These limitations are only some of the many reasons I always convert Excel and CVS data to geodatabase tables. Indexing is another very big reason to not use these formats if you are dealing with data of any significant size. The performance and functionality gains of conversion far outweigh the inconvenience of having to maintain a one-off version of the data in ArcGIS.