Procedure
How can I link my zipcode.dbf with the .agf created from the Data & Maps CD?
Solution:
If you have converted the zipcode.shp from the Data and Maps CD into a .agf
inside Atlas, you will notice the _ID of the .agf contains a record number. That number links the .dbf key column (AGF_LINK) to the .agf _ID column. If the data in the _ID of the geo file does not match any data you have in your table, a link cannot be made between your .dbf table and the zipcode.agf geo file. If you want to link a column of zipcodes in your table to the _ID column of the zipcode geo file, the following steps will prove helpful:
1. Link both the converted .dbf and .agf together, if not already linked. The table will already be linked after the shapefile is converted to a .agf.
2. Click Calc Column.
Column to Fill: _NAME (Make sure this column is empty or can be overwritten)
Expression: zip (use the button to access the desired columns in the expression builder)
3. Click OK. You should now see zipcode data in the _NAME field of your table.
4. Unlink the .dbf from the .agf. The _ID of the .agf cannot be overwritten while being used to linked the .dbf to the .agf.
5. Click Calc Column.
Column to fill: _ID.
Expression: _NAME
You now have ZIP code information in the _ID column that can now be used to link
your .dbf to the .agf that was converted from the CD.