Hi folks. I need to redesign a database to include more complex relationships between 3 variables non of which are mutually exclusive.
These are my 3 tables/fields. Each field is unique in its table.
T_Project.JobNo
T_Accession.AccessionNo
T_Reports.ReportNo
There is no clear relationship between the variables - ie they can all be 1 to 1 or 1 to many or do not have to exist at all.
So I realise now (after 14 years of working with this data), that I need to have what I would think of as holding tables between the primary tables that hold combinations of the variables.
My question is this: Do I do this in one table that holds all 3 variables in non-repeating combinations (although this would need to allow nulls) or do I do it in 3 separate holding tables?
Any advice appreciated.
thanks
These are my 3 tables/fields. Each field is unique in its table.
T_Project.JobNo
T_Accession.AccessionNo
T_Reports.ReportNo
There is no clear relationship between the variables - ie they can all be 1 to 1 or 1 to many or do not have to exist at all.
So I realise now (after 14 years of working with this data), that I need to have what I would think of as holding tables between the primary tables that hold combinations of the variables.
My question is this: Do I do this in one table that holds all 3 variables in non-repeating combinations (although this would need to allow nulls) or do I do it in 3 separate holding tables?
Any advice appreciated.
thanks
Relating 3 tables
