I am learning MS Access and am looking at the Northwind DB. There I find in the relationships an arrow at the "one-end" of some one-to-many relationships and I wonder what that means or what consequences it has. I could not find anything about it asking google (maybe used the wrong search term??) screenshot of one-to-many relationship

I tried to replicate the relationship but did not succeed.

CodePudding user response：

Besides the usual (compared to other databases) attributes related to relationships between tables and referential integrity, in Access you can also specify a Join Type. This does not affect the relationship between the tables as such but will have an influence on the query designer. When you add the tables to the query designer, this will automatically either create an INNER JOIN (with no arrow) where only matching records on both sides will be returned or an OUTER JOIN where all records of one table will be returned but only matching records of the other table (returning the corresponding columns as NULL). The arrow points to the table which might have missing records.

But you can change the join type afterwards in the query designer. So, the informational value of this arrow is very limited.