The primary id (unique identifier) column for each database record.
Can be set in: collection.cfg
This parameter specifies the name of the column in which the database query returns each record's unique primary key, which is required to uniquely identify each record.
The column is expected to be unique for each record, but if repeats occur, only the last record in the result set will be indexed by Funnelback.
Please note that this value is case sensitive, and may be required to be uppercase by some database systems (i.e. Oracle).