Linq submitchanges not updating
If the data structure is changed without your application being updated or knowing about the change then you will run into problems.
In this application, I will be working with the following entity. For example, if we wanted to write everything out to the console we could do this: Adding additional columns If we added an additional column, say email, onto our table then the above could would still work fine however we would never be able to access that additional column until we regenerated our Data Context (see below).
Removing columns Removing columns is when most problems will occur.
If I removed the phone column from the table and execute the query then I would receive a Sql Exception – Invalid column name ‘Phone’.
You can use your own custom logic to override these actions, but the order of submission is orchestrated by a service of the Data Context known as the At this point, any errors detected by the database cause the submission process to stop, and an exception is raised.
All changes to the database are rolled back as if no submissions ever occurred.
Concurrency control is required to prevent two users from trying to update the same data at the same time. The following are the transactions at the bank branches with concurrency control in place In this example, the account is locked while A is processing the transaction.
It can also prevent one user from seeing out-of-date data while another user is updating the same data. The lock is released only after A’s transaction is finished.
if the postback model is an entity you can attach it to a context, and mark it as modified (as the context does not have the original entity it can not track changes). instead use the following logic: post view build new model from postback data (done by binding) db = create new context entity = get original entity update entity from postback model save changes release context Hi Rollo1002, I have checked that I have installed my EF 4.1, but I get the error: Error 1 'Mvc4Test Planning Schedules. Test Planners Schedules Data Context' does not contain a definition for 'Entry' and no extension method 'Entry' accepting a first argument of type 'Mvc4Test Planning Schedules. Test Planners Schedules Data Context' could be found (are you missing a using directive or an assembly reference?
its logic is db = create context entity = get entity make changes to entity object (known to the context, which will track changes) save changes release context but web application are stateless, get view db = create context entity = get entity release context the trick here is the postback model, is not attached to any dbcontext, its a brand new object whose properties are set to the postback values (which may not be all values).
If our query was like below, then it wouldn’t cause an exception as Phone would never be called.
However, when inserting data we will always get a Sql Exception even if the column was not populated as Linq will try and insert null into the column.
When the transaction around the submission is completed successfully, the Data Context accepts the changes to the objects by ignoring the change-tracking information.Tags: Adult Dating, affair dating, sex dating