pseudo index

A dynamic cross-reference of one or more table data fields (columns) that permits an ODBC table (server table) without a unique index to be edited. A pseudo index is not an actual index on the server table, but a cross-reference that the Microsoft Jet database engine can use to support table updates. A pseudo index is necessary only if an ODBC table doesn’t have a unique index, which allows the table to be updated. You don’t need a pseudo index if the table already has a unique index or if there is no need to update the table. (Tables cannot have a unique index if they were intended to be read-only.) In previous versions, pseudo indexes were called index specifications.