[AccessD] Take a formatted number and turn it into a "real" n umber

Colby, John JColby at dispec.com
Fri Jul 16 10:13:52 CDT 2004


Nancy,

You are lucky it is just 10 tables.  It is possible to do this by:

1) Create a NEW database for the migration
2) Link all of the tables from DB1
3) link all of the tables from DB2
4) Create queries that append one table in DB1 to it's matching table in DB2
5) Start by creating SELECT queries (so you can see the data).  In these
queries, take the PK of the table in DB1 and alias it, adding a large number
to it (at least the quantity of records in DB2).  IOW if DB2 has 2000
records in the matching table then the aliased PK in db1 should look like:
	PK: [RealPKFldName]+2000
6) Once you are comfortable you have this right, turn the SELECT into an
append query and append the data into the table

What you have done is simply "bumped" the PK up enough that they will append
in to DB2 without colliding with any existing PKs.  


NOW... any tables that use the PK of that table as a FK... 

You have to "Bump" the FK by that same number (2000 in my example).

You get the idea?

Build a system of queries that do this in order from parent to child table.
Build macros that sequence the queries in the correct order.
Using TEST database copies of DB1 and DB2 run the macros. 
Test that the migration worked.
Fix problems.
Do it again until it works

Once you know that everything is working...

BACKUP the real DB1 and DB2
Run the macro.

You are done.

Doing it this way allows you to do the migration in just the time required
for the update / append queries to work.

JWC

-----Original Message-----
From: Nancy Lytle [mailto:lytlenj at yahoo.com]
Sent: Friday, July 16, 2004 10:45 AM
To: AccessD at databaseadvisors.com
Subject: [AccessD] Take a formatted number and turn it into a "real"
number


I just got handed a database of about 30 tables (about
half are lookups), there are about 10 tables with
varying relationships that are fairly well defined. 
There is an identical - but unconnected - version of
the database at our West Coast location.  
I have now been tasked with merging the two.  At first
I thought it would be easy because it appeared they
were using two different numbers schemes for the PK's
turns out they just formatted them to "look different"
but the matching tables use the same Autonumber -
start from 1 - field type.  So now I have to figure
out a way to merge them without messing up all the
relationships.  
Does anyone have any ideas?  Both databases are still
being used so I have to come up with a way I can do it
with the least down time possible.
TIA,
Nancy
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