May be the following explanation from Oleg will help you..
The idea of concatenation is to concatenate tables (not fields!) when more than 1 table have more than key in common. For example:
load Item, Customer, Date, Order Quantity from Orders;
concatenate load Item, Customer, Date, Invoiced Quantity from Invoices;
In this example, the resulting table will store both Orders and Invoices, with the common fields Item, Customer and Date. The other two fields - Order Qiantity and Invoice Quantity will only have a value when available.
This way, you avoid synthetic keys and avoid the need in creating a Link Table. The nice thing about concatenation is that now you can also load tables with other repeating fields, for example:
Customer, Date, Budget Amount
Customer and Date will be shared fields, but not the Item.
May be the following explanation from Oleg will help you..
The idea of concatenation is to concatenate tables (not fields!) when more than 1 table have more than key in common. For example:
load Item, Customer, Date, Order Quantity from Orders;
concatenate load Item, Customer, Date, Invoiced Quantity from Invoices;
In this example, the resulting table will store both Orders and Invoices, with the common fields Item, Customer and Date. The other two fields - Order Qiantity and Invoice Quantity will only have a value when available.
This way, you avoid synthetic keys and avoid the need in creating a Link Table. The nice thing about concatenation is that now you can also load tables with other repeating fields, for example:
Customer, Date, Budget Amount
Customer and Date will be shared fields, but not the Item.
