Here is a scenario: Thre is a table "Users" that contains UserId and UserName. There is another table "Organisations", where there are fields OwnerId, which contains UserId, and ProjectManagerId also contains UserId. And one more table, Orders, with fields AccountId and SalesRepId. You want Orders linked Organizations by AccountId, and not by any users. to deal with all these multiple User roles, create map:
UserMap: MAPPING SQL SELECT DISTINCT UserId, UserName FROM Users;
And use it as many times as you want: applymap('UserMap', OwnerId) as "Account Owner" applymap('UserMap', ProjectManagerId ) as "SaleProject Manager" applymap('UserMap', SalesRepId) as "Sales Rep" ... In the other words, it is used here as a picklist. Not the only possible use of the aplymap, but probably the most typical.
