what happens to my dataset in case of unexpected failure

Question

i know this has been asked here. But my question is slightly different. When the dataset was designed keeping the disconnected principle in mind, what was provided as a feature which would handle unexpected termination of the application, say a power failure or a windows hang or system exception leading to restart. Say the user has entered some 100 rows and it is modified at the dataset alone. Usually the dataset is updated at the application close or at a timely period.

In old times which programming using vb 6.0 all interaction used to take place directly with the database, thus each successful transaction was committing itself automatically. How can that be done using datasets?

Answer 1

A DataSet can be serialized very easily, so you could implement your own regular backup to disk by using serialization of the DataSet to the filesystem. This will give you some protection, but you will have to write your own code to check for any data that your application may have saved to disk previously and so on...

You could also ignore DataSets and use SqlDataReaders and SqlCommands for the same sort of 'direct access to the database' you are describing.

Answer 2

DataSets are never for direct access to database, they are a disconnected model only. There is no intent that they be able to recover from machine failures.

If you want to work live against the database you need to use DataReaders and issue DbCommands against the database live for changes. This of course will increase your load on the database server though.

You have to balance the two for most applications. If you know a user just entered vital data as a new row, execute an insert command to the database, and put a copy in your local cached DataSet. Then your local queries can run against the disconnected data, and inserts are stored immediately.