an Access DBMS with NO RELATIONSHIPS?

[kt]

Hi
In looking at a database within my new employer and have noticed that there
are no relationships set up. Some of the tables are linked from external
databases and many are created ad-hoc by various novice users.
I have been asked to build reports based on the data in this database - I am
leary as there are no relationships - leading me to believe the data does not
have referential integrity and is not reliable.
Does anyone know if my fear is irrational since many (but not all) of the
table are linked from an external source (probably star schema warehouse)?

 

[Guest]

In Access, it is not possible to use Declarative Referential Integrity
on external data. DRI only applies to MDB tables in one MDB
database.

In Access, you won't be able to see relationships defined in a
data warehouse.

In Access, you can declare relationships between external tables,
or between external and internal tables, but those relationships
are meaningless - they are only helpful as guidelines when building
queries.

Access is a good platform for building reports based on external
data.

The quality of the external data is up to you: Access can't help
you there.

(david)

 

[John Vinson]

Hi
In looking at a database within my new employer and have noticed that there
are no relationships set up. Some of the tables are linked from external
databases and many are created ad-hoc by various novice users.
I have been asked to build reports based on the data in this database - I am
leary as there are no relationships - leading me to believe the data does not
have referential integrity and is not reliable.
Does anyone know if my fear is irrational since many (but not all) of the
table are linked from an external source (probably star schema warehouse)?

You cannot establish relationships with RI enforced to linked tables
in any case... but you're quite right, unless the relationships are
enforced *somewhere* (in the data warehouse, in the code which
extracts the data, or other) then the Garbage In - Garbage Out
phenomenon will certainly rear its ugly head.

You might want to do some testing - try the Unmatched Query wizard on
some pairs of tables which should logically be related, to see if
there are "orphan" records. I'd be rather surprised if there are not.

John W. Vinson[MVP]