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Posts Tagged ‘EF Codefirst’

Define Composite Key in Model.(Core, EF Code First)


When there are composite keys in database table and when you try to put data annotation it will throw below error

Entity type ‘Orgmember’ has composite primary key defined with data annotations. To set composite primary key, use fluent API

The above code will not work and throw an error

Here is the solution for this problem

Step 1: Modify your modal class like

Step 2: Use the fluent API to set up a composite key.

Hope it helps!

EF code first – Model compatibility cannot be checked because the database does not contain model metadata

October 10, 2017 Leave a comment

This suggests that migration table is out of sync (even if your data isn’t), and that’s been part of the db schema now (since 4.3 I think – under system tables).

There could be many reasons and ways to experience that error , but most of the time…

The problematic part is some combination of manually backing/restoring the full database with code changes alongside – I’m not entirely certain as to why always.

In short, even if Db-s are the same migration table data might not be – and hash comparison may fail (still full restore sounds like good enough – but you have ‘two sides’).

What works for me is to use
Update-Database -Script

That creates a script with a ‘migration difference’,
which you can manually apply as an SQL script on the target server database (and you should get the right migration table rows inserted etc.).

If that still doesn’t work – you can still do two things…

a) remove the migration table (target – under system tables) – as per http://blogs.msdn.com/b/adonet/archive/2012/02/09/ef-4-3-automatic-migrations-walkthrough.aspx comments in there – that should fail back to previous behavior and if you’re certain that your Db-s are the same – it’s just going to ‘trust you’,

b) as a last resort I used – make a Update-Database -Script of the full schema (e.g. by initializing an empty db which should force a ‘full script’),
find the INSERT INTO [__MigrationHistory] records,
just run those, insert them into the database,
and make sure that your databases – and code match,

that should make things run in sync again.

(disclaimer: this is not a bullet proof to work at all times, you may need to try a few things given your local scenarios – but should get you in sync)

Also this will work

I found the code will work by changing

static LaundryShopContext()
{
Database.SetInitializer<LaundryShopContext>(
new DropCreateDatabaseIfModelChanges<LaundryShopContext>());
}
into

static LaundryShopContext()
{
Database.SetInitializer<LaundryShopContext>(
new DropCreateDatabaseAlways<LaundryShopContext>());
}