ArcMap won't let me add fields to a table?

Question

For some reason, my ArcMap will not let me add a field in my tables, regardless of the table. Further, the "Add field" option is grayed out. In ArcCatalog, no extra field is available to be typed in.

I've quit the program, restarted my computer, and I've tried with different tables. I've also tried with shapefiles, where there is no problem. Also, I am not currently in an editing session.

These tables are stored on my computer, I should have permission to modify everything as these are all my files, and are not in use by anyone else. I have tried .csv, and .xls files and are simply stored in my project specific files. Standard operating procedure of mine for years.

Answer 1

ArcGIS does not have full functionality for csv or Excel files. They are essentially for import and other input tasks. It is like asking why Excel cannot add rows or columns to my file geodatabase.

It is likely nothing to do with permissions. You are trying to use a wrench to turn in a screw. Use a screwdriver (geodatabase table in this terrible analogy).

This link will help you understand. Here are some key points to consider from the ESRI help site.

• ArcGIS supports both Excel 2003 and earlier .xls files and Excel 2007 .xlsx files.
• If you have an .xlsx file you want to use in ArcGIS but do not have Excel 2007 installed, you will need to install the 2007 Office System Driver.
• Excel tables are read-only in ArcGIS as well as in Excel when you have a workbook open in ArcGIS.
• Field names are derived from the first row in each column of the worksheet. You can view the properties, set aliases for the field names, and set field visibility on the Fields tab of the table's Properties dialog box.
• Excel does not enforce field types for values during data entry like standard databases do. Therefore, the field type specified in Excel is not used in determining the field type exposed in ArcGIS. Instead, field type in ArcGIS is determined by a scan of the values in the first eight rows for that field. If the scan finds mixed data types in a single field, that field will be returned as a string field, and the values will be converted to strings.
• Numeric fields are converted to the double data type in ArcGIS. Excel tables behave like other tables that don't have an ObjectID field. This means you will be unable to edit, perform relates, or make selections on the map.
• Excel file support in ArcGIS uses Microsoft OLE DB Provider for Jet 4.0 and its supporting Excel Indexed Sequential Access Method (ISAM) driver.
• You can directly export to Excel by using the Export To Excel tool from the Geoprocessing Model & Script Tool Gallery. You can also export tabular data to dBASE format, which can be opened in Excel 97/2003 and saved as an .xls file. Microsoft discontinued support for .dbf files in Office 2007.
• You can still open an Excel file through an OLE DB database connection.