I’ve complex object (nested properties, collections etc) in my ASP.NET MVC C# application. I don’t need to save it into the multiple tables in the DB, serializing the whole object and store it like a whole is ok.
I plan to serialize the whole object (in something human-readable like JSON/XML) and store in text field in the DB.
I need to later load this object from the DB and render it using strongly-typed view.
Here comes the question: in the future the class of the object can change (I can add\remove fields etc). But serialized versions saved into the DB before will not reflect change.
How to deal with this?
You should write some sort of conversion utility every time you significantly change structured, serialized messages, and run it as part of an upgrade process. Adding or removing fields that are nullable isn’t likely to be a problem, but larger structural changes will be.
You could do something like implement IXmlSerializable, peek at the message and figure out what version the message is and convert it appropriately, but this will quickly become a mess if you have to do this a lot and your application has a long lifecycle. So, you’re better off doing it up front in an upgrade process, and outside of your application.
If you are worried about running the conversion on lots of records as part of an upgrade, you could come up with some ways to make it more efficient (for example, add a column to the table that contains the message schema version, so you can efficiently target messages that are out of date).