Sets or returns a value that indicates whether an Index object represents a primary key index for a table (Microsoft Jet workspaces only).
Settings and Return Values
The setting or return value is a Boolean that is True if the Index object represents a primary key index.
The Primary property setting is read/write for a new Index object not yet appended to a collection and read-only for an existing Index object in an Indexes collection. If the Index object is appended to the TableDef object but the TableDef object isn't appended to the TableDefs collection, the Index property is read/write.
Remarks
A primary key index consists of one or more fields that uniquely identify all records in a table in a predefined order. Because the index field must be unique, the Unique property of the Index object is set to True. If the primary key index consists of more than one field, each field can contain duplicate values, but each combination of values from all the indexed fields must be unique. A primary key index consists of a key for the table and usually contains the same fields as the primary key.
Note You don't have to create indexes for tables, but in large, unindexed tables, accessing a specific record can take a long time. The Attributes property of each Field object in the Index object determines the order of records and consequently determines the access techniques to use for that index. When you create a new table in your database, it's a good idea to create an index on one or more fields that uniquely identify each record, and then set the Primary property of the Index object to True.
When you set a primary key for a table, the primary key is automatically defined as the primary key index for the table.