Does EF 4 have built in audit / logical delete support? After using SubSonic and getting use to how nicely this was handled automagically I was hoping I might have the same luck with EF 4 but haven't found any documentation.
Not built in, no. You could build an audit feature fairly easily with the tracing provider. For soft deletes, you can handle ObjectContext.SavingChanges() to change a delete to an update and filter "deleted" records at the data service layer.
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I use Model-first with EF, and I want to have an automated gap DDL script when I change my model. With "Entity Framework Database Generation Power Pack" We had it in past, but I read that was not supported in VS2012.
Any changes about that?
For Who dont't understand this need, I would like to remmember that in production enviroments, development team dosen't have access to DB. We must create and send to production Support team, DDL deployment scripts that preserve data and all DB without any recreation.
You should have a look at Database.SetInitializer, which mainly determines what happens if there is no database present when the application is started for the first time, and migrations which can be used to update the datebase when a new application version (which requires an updated database) has been deployed. If the built-in support for migrations data aren't enough, you also have the ability to add raw SQL data to handle migrating to a new version.
I'm using Entity Framework 5 model first. Say I've deployed the application and I'd like to upgrade an EF entity with new columns, basically adding columns to the table.
What is the best way to upgrade the existing database without losing data? For example I have a User table that I add two new columns to. If I try to script a schema change the tables will need to be dropped in order to add the new columns. Is there a way to update the tables without needing to recreate them? Thanks!
This may be a late answer but I have had the same problem and could just find one solution, there is an application that can update the model-first generated databases without losing the data.
It can directly open the model file and update the database tables.
It also installs some extensions on Visual Studio that I have not personally used but may be usable.
The name is Entity Developer and there are some editions of the application listed here:
Entity Developer Editions
The free edition is usable only for 10 entities or less that may not suit your needs but the Professional edition is usable for 30 day as a trial that may help you do the job. The only solution I could find on the net was this one.
Hope it helps you with the problem.
I have been working on a side project for the last few weeks, and built the system with EntityFramework Code first. This was very handy during development, as any changes i needed to make to the code were reflected in the DB nice and easily. But now that i want to launch the site, but continue development, i dont want to have to drop and recreate the DB every time i make a tweak to a model...
Is there a way to get EF to generate change scripts for the model change so i can deploy them myself to the production server? And how do i use the database somewhere else (Windows Service in the background of the site) without having to drop and recreate the table, and use the same model as I have already? Kind of like a "Code first, but now i have a production DB, dont break it..."
Personally i use the builtin data tools in VS2010 to do a database schema synchronization for updating production.
Another cheaper tool if you dont have VS Premium is SQLDelta which ive used in the past and is really good.
Both tools connect to the two database versions and allow you to synchronise the table schemas first. Both also have an export to SQL script functionality.
Comming up for EF is Migrations which allows you to solve just this problem within your solution however its still in beta. Migrations lets you describe upgrade and downgrade events for your database in code.
No RTM version of EF has this feature. Once you go to production you must handle it yourselves. The common way is to turn off database initializer in production and use some tool like VS Premium or RedGate Database compare to compare your production and dev database and create change SQL script.
You can also try to use EF Migrations which is exactly the tool you are asking for. The problem is it is still beta (but it should be part of EF 4.3 once completed) so it doesn't have to work in all cases and functionality / API can change in RTM.
I've been working Entity Framework trying to get better with it. I'm liking what I'm seeing thus far but now have a question. With this new 'Code First' approach (from the CTP 4 download) we can now use EF from a code first approach, but I'm trying to find out if one can use an existing EDMX file with this approach.
I have a project I'm working on which has an EDMX file and I notice the ModelBuilder has a RegisterEdmx method but am not finding a lot out there on whether this will allow to use an existing EDMX file with my code first approach.
Also, I know with this new CTP things like RecreateDatabaseIfModelChanges are avilable but these options drop the database and recreate it, wont this cause all your data to be lost if you ever change your models? Is there something I'm missing here?
I can't speak to using previously generated EDMX files but there is support to use Code First with existing databases. As for the automatic Recreate, yes, this will kill all your data. This is meant only in rapid development where the persistence of data doesn't matter (and, in fact, is likely unwanted as you discover issues with business logic and want a clean start with your updates.)
This is meant only as a quick way to develop. As of (when Scott Guthrie blogged about the CTP - jump to section 5) there are no data migration features available. Your options are to manually update the database to match your model, delete the database and let it be recreated or set the automatic recreate option. Only the first option is non-destructive to your data.
I'm in the process of looking around at options for a back office tool. On the face of it the tool is simple CRUD so I was immediately attracted to Dynamic Data on top of Entity Framework (we're definitely a Microsoft shop!).
The problem is that future requirement is to support versioning. By this I mean :
User performs a series of updates to a series of entities
When they are happy they submit the changes
Changes persisted to the DB along with enough info to support a rollback
Elsewhere we've got handcrafted app that :
Includes a version id that is incremented as each new row inserted - i.e. we don't update we add a new row
A work item table ties together the changes using the version id along with the entity type (table)
So, the question is, how would I achieve a similar end result using entity framework and dynamic data?
If entity framework, etc isn't appropriate - what would you use (.Net)?
Thanks,
Alan
One solution would be to move the logic for the versioning to database triggers. This way you are able to use a standard Dynamic data on top of Entity Framework, and retrofit versioning by running a set of database scripts.
I would like to mention that in the new Dyanmic Data Preview 3 there is a new feature DomainService which supports Roles based security please see David Ebbo's Serssion from MIX09 here Microsoft ASP.NET 4.0 Data Access: Patterns for Success with Web Forms MIX09-T47F