SPROC to update record: how to handle unchanged values?

If you can change the DAL (without changes being discarded once the layer is "regenerated" from the new schema when changes are made), I would recomend passing a structure containing the column being changed with values, and a structure kontaing key columns and values for the update This can be done using hashtables, and if the schema is known, should be fairly easy to manipulate this in the "new" update function If this is an automated DAL, these are some of the drawbacks using DALs.

If you can change the DAL (without changes being discarded once the layer is "regenerated" from the new schema when changes are made), I would recomend passing a structure containing the column being changed with values, and a structure kontaing key columns and values for the update. This can be done using hashtables, and if the schema is known, should be fairly easy to manipulate this in the "new" update function. If this is an automated DAL, these are some of the drawbacks using DALs.

You could implement journalized change tracking in your model objects. This way you could keep track of any changes in your objects by saving the previous value of a property every time a new value is set. This information could be stored in one of two ways: As part of each object's own private state Centrally in a "manager" class.In the first solution, you could easily implement this functionality in a base class and have it run in all model objects through inheritance.

In the second solution, you need to create some kind of container class that will keep a reference and a unique identifier to any model object that is created and record all changes in its state in a central store. This is similar to the way many ORM (Object-Relational Mapping) frameworks achieve this kind of functionality.

There are off the shelf ORMs that support these kinds of scenarios relatively well. Writing your own ORM will leave you without many features like this. I find the "object.Save()" pattern leads to this kind of behavior, but there is no reason you need to follow that pattern (while I'm not personally a fan of object.Save(), I feel like I'm in the minority).

There are multiple ways your data layer can know what changed and most of them are supported by off the shelf ORMs. You could also potentially make the UI and/or business layer's smart enough to pass that knowledge into the data layer. Two options that I prefer: Generating/hand coding update methods that only take the set of parameters that tend to change.

Generating the update statements completely on the fly.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.