concurrent accesses on EntityFramework 5.0 on insert

Question

I'm facing some issue with Entity Framework 5.0.

I have a WCF SOAP webservice with a method that create 2 entities in two mysql tables.

Entity B contains further informations to Entity A : so Entity A Primary Key is the same as Entity B PrimaryKey (like a Foreign Key).

When I create the whole entity (A+B), I don't have PK from Entity A used for entity B. So I need to save on context Entity A, then Entity B, then savechanges to commit.

    taskDao.Save(task);
    taskRenderingDao.Save(taskRendering);
    taskDao.SaveChanges();

The problem is, when I have concurrent accesses, It happens that context is a bad state, and it returns me the following error : "unique constraint violating on PK".

Someone can help me to solve it ?

Thank you Guillaume.

You need to create new db context per SOAP request, or introduce locking mechanism — Darjan Bogdan, Mar 21 '17 at 10:49
@DarjanBogdan locking mechanish as I do for a threading method ? — Guillaume P., Mar 21 '17 at 10:51
@GuillaumeP. yes because that's actually happening on your WCF service, server creates 2 threads (for 2 SOAP requests) which work concurrently on the **same** EF (db) context. — Darjan Bogdan, Mar 21 '17 at 10:56
"The problem is, when I have concurrent accesses, It happens that context is a bad state" - if you never use same context from multiple threads - it won't be in bad state. So just don't ever use same context from multiple threads (and better not reuse context at all). — Evk, Mar 21 '17 at 10:56
If you are reusing your context object, you're going to have a very bad time... — DavidG, Mar 21 '17 at 10:58
@RicardoSerra I used static context for this app, so I assume it is a bad way to do it ? — Guillaume P., Mar 21 '17 at 10:58
Yes, that's a really bad idea. Always create a new context object, never reuse it. — DavidG, Mar 21 '17 at 10:59
@DavidG yes I see it. I will try to use a locking mechanism. Do you prefer a new one maybe ? — Guillaume P., Mar 21 '17 at 10:59
@DarjanBogdan I tried to lock access to insert method used by EF 5 but it doesn't work. May you help me? — Guillaume P., Mar 21 '17 at 13:43
@GuillaumeP. I strongly suggest you not to use static EF context, please read more about the [topic](http://stackoverflow.com/questions/888185/entity-framework-context-as-static). However if you want to proceed with locking, please post your solution so I can help you properly. — Darjan Bogdan, Mar 21 '17 at 13:51
@DarjanBogdan It's ok, the only way I solve it is by using a new context as you tell me. But locking mechanism didn't work maybe because I failed it. Thank you for you help (y) — Guillaume P., Mar 21 '17 at 14:30

concurrent accesses on EntityFramework 5.0 on insert

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