What characters should not be used in ArcGIS for field names and table names?

Answer

For ArcGIS to work with multiple data types, certain characters in field or table names are not supported. These characters include spaces, hyphens, such as in the term 'x-coord', brackets, and other special characters. These limits are imposed so that ArcGIS is able to function with the maximum amount of data types.

• Eliminate any characters that are not alphanumeric character or an underscore.
• Do not start field or table names with an underscore or a number.
• It is necessary to edit the field names in delimited text files to remove unsupported characters before using them.

The limit for the length of field and table names depends on the underlying database management system (DBMS). Consult the DBMS documentation for information on naming limits for a particular DBMS. A dBASE field name can be up to 10 characters long, and there is no limit on the length of the table name.

• For coverages, use up to 16 letters or numbers. Coverage items or field names must begin with a letter, and cannot contain spaces.

Note:
Microsoft SQL Server databases named with a number at the beginning are also not supported.