Is PK is the one through which we associate between tables

[Tanisha_36]

hello
i have two table one A:- with oid,Order date,Shipped date,delivery date,category
and another with B:- Category,date,target,KPI

I know in table A oid is PK but oid cant communicate with tale B
so in such cases how should I proceed

Thank you in advance

[marcus_sommer]

I think you could associate the tables per category and/or combined with any of the date-fields, maybe like:

category & '|' & date as KEY

Another approach could be to concatenate both tables because the data are quite the same - just the direction of the current- vs. target-data is reversed. Having a different granularity like date- + article-level against a month- and category-level is not a big challenge. Concatenating has the benefits of being very simple and avoiding any trouble with NULL and/or missing key-values on any side.