Specifies whether this index defines the primary key for the table.
Details
This keyword specifies that this index should be reported, via SQL, as being the primary key for this class (table).
A PrimaryKey index also behaves like a unique index. That is, for the property (or the combination of properties) that you use in this index, InterSystems IRIS enforces uniqueness. It is permitted, but redundant, to specify the Unique keyword as true in this index definition.
For a primary key index, InterSystems IRIS generates methods that you can use to open objects, check existence of objects, and delete objects; see Open, Exists, and Delete Methods.
Example
Index EmpIDX On EmployeeID [ PrimaryKey] ;
Default
If you omit this keyword, the primary key for this table is not formed by the properties on which this index is based.