Using one-to-one relationship

Anonymous
2011-02-07T01:32:55+00:00

For various reasons, I need to break up a large table into smaller tables.  I've set up the smaller tables with one-to-one relationships.

If I assign a form's record source using just one of the smaller tables (and its fields), the form opens correctly showing the first record.  And, I can move through all the records using the Access record controls.

If I add one or more of the smaller tables (which participate in the one-to-one relationship with the original table), the form opens but no records are available - i.e., it opens as if I asked it to display a new record, and it doesn't recognize that there are other records available.

The one-to-one relationships are correctly set, with each table's primary key being a single key.

I have form controls that need to be bound to several of the one-to-one tables, so several tables need to be the form's record source.

As an example:  Table A has an autonumber primary key field, AID, and another field, Aname.  Table B has a primary key field BID (numeric long integer type) joined to AID in a one-to-one relationship (with referential integrity), and another field, Baddress.

If Table A is a recordsource for a form, the value of field Aname appears on the form and I can move through all Table A records.  As soon as I add Table B (along with Table A) as a recordsource, the form opens with no records available (i.e., a blank form as if I told it to go to a new reocrd).

I realize I can resolve this through a single large table, but that's what I'm trying to avoid. 

Has anyone worked with one-to-one relationships enough to have run into this problem?  And come up with a solution?

Thanks for any help.

Mike

Microsoft 365 and Office | Access | For home | Windows

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ScottGem 68,840 Reputation points Volunteer Moderator
2011-02-10T19:13:03+00:00

Mike,

I'm going to agree with Roger yet again. Helping you has been a pleasure and we will be here to support you as your project continues.

The main difference between bound and unbound forms is that, with a bound form, Access handles all the I/O between the form and the table. With an unbound form, the user has to write code (VBA), to handle the I/O. The complexity of that code can vary widely depending on the usage and purpose of a form. For example, a form solely for entering new records is fairly easy to code. But a form for retrieving data and populating the unbound controls, can be very complex. The coding involved depends on the table structure and form layout. Personally, I'm lazy and tend to use bound forms wherever I can.

There is only ONE circumstance in Access where a child record can be created with an automatically populated FK. And that's when using a subform. When you correctly link a subform to the main (parent) form, then any records created in the subform have the FK automatically populated. This is one of the reasons I said that subforms are a very powerful feature. But this only works with bound forms. So, in every other circumstance, when you add a record to a child table, you have to make sure the FK is populated correctly.

Hope this helps, Scott<> P.S. Please post a response to let us know whether our answer helped or not. Microsoft Access MVP 2010 Blog: http://scottgem.wordpress.com Author: Microsoft Office Access 2007 VBA Technical Editor for: Special Edition Using Microsoft Access 2007 and Access 2007 Forms, Reports and Queries

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Anonymous
2011-02-10T18:15:24+00:00

Mike,

It's posts like this that makes the whole process of answering questions here worth while.  I think we've seen a lightbulb go off above your head <grin>

As you no doubt realize, there are two distinct knowledge sets necessary for database development: design and implementation.  The Design set is universal and can be applied to any DBMS implementation.  The Implementation set is specific to the DBMS.

For Design knowledge, I recommend Michael Hernandez' "Database Design for Mere Mortals".  I taught 12 years of college courses in db design from that book.  It was a revelation to me.

For Access Implementation knowledge, I recommend "Access Cookbook" by Ken Getz, Paul Litwin, and Andy Baron.  I learn best from examples and this book is a set of common problems and solutions in Access development.  It's not really a book that you read through.  It's best used to find how to solve a specific problem.

I created the samples on my website (www.rogersaccesslibrary.com) with the same idea in mind. 

Good luck!

-- Roger Carlson

MS Access MVP 2006-2010

www.rogersaccesslibrary.com

If you want a detailed answer, ask a detailed question!

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  1. Anonymous
    2011-02-07T03:26:31+00:00

    Gina,

    I have a similar issue, but I have to split up one big table into two tables with an inner join. All records in one table will link to a corresponding record in the other with no orphaned records. The join is cascaded.

    My problem is adding a single record in this arrangement. In a form, if I try to add a record to both tables, I can add data to to one table, but don't know how to add it to the other. With one big table it was automatic. Now I have to enter a matching key field in both tables to link them. How do I do this?

    Thanks,

    .. Jim ..

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  2. Anonymous
    2011-02-07T03:20:45+00:00

    Mike,

    Put your tables in a single query and use that as your record source for the form. This will link all your fields to the form.

    .. Jim ..

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  3. Anonymous
    2011-02-07T02:03:55+00:00

    Sounds like you are using an INNER JOIN which will only show the records if they exist in all tables.  I would look at the RecordSource and change your JOIN type so you get all the records to show.

    --

    Gina Whipp

    Microsoft MVP (Access)

    Please post all replies to the forum where everyone can benefit.

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