Dynaset (Inconsistent Updates)

[Sess]

In Access2003, in the property of a form on the Record Type there is a choice of Dynaset, Snapshot and Dynaset (Inconsistent Updates). I understand the Dynaset you can update, Snapshot you can not, but what is with the "Inconsistent Updates"?
Thank you.

 

[Banana]

As far as I'm aware, it's basically same thing as dynaset except that the updates aren't immediate. However, I've found this to be unnecessarily risky and I've yet to find a practical application for this. I just use either Dynaset or Snapshot.

 

[Sess]

Thank you. More curiosity then anything else.
I read on a post on a other forum that you need the setting if to update multiple tables from a form when there is a complex relationships between the tables like "one to many to many" or "many to one to many" but that is the only reference I have ever seen for the use of it. Just seems like a fix for badly planned database application.

 

[Banana]

I would agree that this is not necessary for such scenario as you can just do fine with a proper form-subform, using dynasets for both. One-many-many or many-one-many (I hope this means a sibling relationship and not something else!) can be modeled using nested subforms or subforms side by side.

FMS has a nice demo on synchronizing two sibling subform. I used something similar this and neither their method nor mine require use of inconsistent updates.

 

[georgedwilkinson]

Actually, this may be useful if your design utilizes polymorphism with a multiple table implementation.

 

[Banana]

Hmm. Care to elaborate, George?

The thing that bother me most about inconsistent updates is that there seems to be no mechanism to trigger the updates as was the case with ADO's disconnected recordset but perhaps I didn't completely understand the concept. Would like to see a practical example.

 

[georgedwilkinson]

Remember, I said "may" (I always leave myself an out). I've been working on an example for 10 years that you and I have discussed before. When it gets down to it, I'll discuss it with you then and try to remember to update this thread.

 

[Banana]

Ah, as always, the demon in details get me every time. Looking forward to seeing it. I have been likewise wondering about the utility of inconsistent updates - they wouldn't have had put it in there for no reasons, surely.

 

[vbaInet]

Remember, I said "may" (I always leave myself an out). I've been working on an example for 10 years that you and I have discussed before. When it gets down to it, I'll discuss it with you then and try to remember to update this thread.

10 years George :O You should be awarded a PhD (or maybe you have one already, who knows!)

 

[georgedwilkinson]

I wish. It's been 10 years because I'm too lazy to finish it.

 

[Sess]

Thank you for the link for the FMS demo to synchronize two subforms. That is cleaver to have a second field that is hidden so you can synch the two subforms.
I got lost on the polymorphism part but if you have been trying to figure it out for 10 years then I had better not get into it.

 

[Banana]

Glad the link helped.

Polymorhpism is a concept in object oriented programming and very useful one. Basically it enables us to treat two different objects as if they were same, which is good in term of coding because it allow us to worry less about the implementation as long the class is presumed to act this way (whether by using an interface describing its available range of actions or by inheriting from a common base class). We don't usually deal this in the Access world because VBA is object-based but not object-oriented and fundamentally a procedural language. This is good thing because it allows a non-programmer to focus on solving the problem (e.g. doing some kind of calculation) without getting mired up in object quagmire.

However, there has been a long standing conflict between the relational database world and the programming world... tables are not exactly objects but there are many people who feel that being able to treat relational things as an object would make it easier for them to encapsulate complex logic. This is referred to "object-relational impedance", of which the subject has been extensively discussed.

Anyway, that's the gist so yes, it's quite cerebral.

 

[georgedwilkinson]

Anyway, that's the gist so yes, it's quite cerebral.

It takes somebody like Banana, or maybe Leigh, to even follow along. I just wrote the words 'cause I though they sounded cool.

 

[Sess]

Thank you. That is right up there so I do not think I will start a discussion about that with my mentor.

 

[Banana]

It takes somebody like Banana, or maybe Leigh, to even follow along. I just wrote the words 'cause I though they sounded cool.

I don't know about Leigh, but I hear that Banana uses Wikipedia to make him look smarter than he really is. That dastardly bastard!

 

[gemma-the-husky]

google search found this from 10 years ago. does it mean anything to you


http://www.access-programmers.co.uk/forums/archive/index.php/t-18314.html


and this one on another forum, featuring our own ChrisO

http://www.mdbmakers.com/forums/showthread.php?t=5720

 

[Sess]

So that leads me to think that the Dynaset(Inconsistent Updates) is an override for when a query has informed you that you may not update the data. Somehow I felt it was referral to the data being displayed rather than a quasi-update permission bypass type of thing.

 

[Banana]

No, I wouldn't put it that way. Reading the links it became apparent to me that I held a misconception - I assumed the inconsistent updates were referring to something similar to a disconnected recordset.

If I have understood the links it enables you to update all tables in a recordset. To help illustrate this, create a query that joins a one-many table (perhaps a customer and order table) then open it in datasheet. (We should be using forms but here its to demonstrate) Now insert a new customer in this datasheet. You will be able to do so. Now insert an order in the same row. You'll find its locked for regular dynaset. You'd have to save the record by moving off then back or hitting record save befroe you can then fill in the blanks for the order portion.

Now if I've understood it, inconsistent update enable you to fill out both portion on same row without needing to save either portion first.


Note: I typed it then got distracted and am posting it quite late. Apologies.

 

[Utmost]

As I was reading this forum I found the answer so I thought I would post it.

"..Dynaset, allows you to update any fields on the Many side of a join. It also lets you change values on the one side of a join if you have defined a relationship between the tables and enabled Cascade Update Related Fields in the Edit Relationships dialog box. If you choose Dynaset (Inconsistent Updates), you can update any field that isn't a result of a calculation, but you might update data that you didn't intend to be updateable."

 

[cmohanc]

Hi ,
i am finding use for this Inconsistent updates. I have to display / data entry from one table but need to get master data from the other related tables as well. I can do this by a complicated query and save record only to the required table.
Seems to be very useful