You've indicated in a comment that what you want is for a number of users o be able to see different data rows in the same table or tables
That's actually quite quite straightforward: you just need to define, for each user (or user type), the criteria which determine which data rows they are supposed to be able to see, then write a Where clause which selects only those rows. It's generally a bad idea to hard-code users's identities in a database and what data they are permitted to see and what operations they are permitted to carry out on the data.
It's hard to give a concrete example without getting into details of what you are wanting to do, but the following simple example might help.
Suppose you have a table of Customers, and one user is suposed to deal with the USA, the second user deals with France and the third with the rest of the world.
In your app, you could have an enumerated type to represent this:
type
TRegion = (rtUSA, rtFR, rtRoW); // RoW = Rest of the World
Then you could write a function to generate the Where clause of a SQL Select statement like this:
function GetRegionWhereClause(const ARegion : TRegion) : String;
begin
Result := ' Where ';
case ARegion of
rtUSA : Result := Result + ' Customer.Country = ''USA''';
rtFR : Result := Result + ' Customer.Country = ''FR''';
rtRoW : Result := Result + ' not Customer.Country in (''USA'', ''FR'')'
end; { case }
end;
You could then call GetRegionWhereClause when you generate the Sql to open the Customers table.
Similarly define for each user type what operations they are permitted to carry out on the data (Update, Insert, Delete). But implementing that would be more a question of selectively enabling and disable the gui functionality in your app to do the tasksin question.
