How do I know what is the Child table and Parent table when creating a join
When creating a 1:M join in Incorta, for example between Customer and Sales tables, the Child table is the 'Many' table, and the Parent table is the 'One' table. In this example, Sales is the Child table and Customer is the Parent table.
A rule of thumb when creating these joins is : The column(s) from the Parent table used to define the join must constitute a Primary key of this table. For instance if the join in the example above is Sales.Customer_id = Customer.Customer_id then Incorta expects Customer_id to be a primary key of the Customer table. If your customer table is a type2 dimension, then its primary key would typically be (Customer_id, start_effective_dt). In this case look for another article on joining to type 2 dimensions in Incorta to see how you can join between the Sales table and the Customer table.