Creating primary indexes
You can create a primary index in the Table designer or the Manage Indexes dialog box. If the table type you are creating does not support primary indexes, these options are not available. dBASE Level 7 and Paradox table types both support primary indexes.
To create a primary index,
Open the table in the Table designer.
Choose Structure|Define Primary Key to display the Define Primary Key dialog box.
Choose the Primary Key fields from the Available Fields list. Click the arrow to add (or remove) fields from the Fields Of Primary Key list box.
Note
In the case of Paradox tables only, the first field in the table must be the primary key or part of a composite primary key. If the field you want to be the primary key is not currently the first one in the table, you have to move it up in the Table designer to be the first field. The dBASE format does not share this limitation.