How did you handle the concurrency Did you use a timestamp, did you clone and then merge the objects again or did you use self-tracking entities (3 most used approaches).If you didnt handle the concurrency, I guess thats the problem.So you need to retrieve the object, make a change, and save it.When you call SaveChanges the context evaluates all the objects it is tracking to determine if they are added, changed, or deleted and issues the appropriate SQL to the connected database.
Only thing working is - you need to retrieve the object, make desired changes, and save it via db.SaveChanges(). As long as you provide a correct primary key, you can set the EntityState to Modified and SaveChanges() will work, provided you dont break some other integrity constraint defined on the table. I assume SaveChanges() call is required after setting values. Entity Framework Update Just FineMake sure the IDs match between the two models and it will update just fine. In case when you dont have book with search reference (i.e. ID) itll create new row and it can be an issue in come cases (for example, you have an API which needs to return you 404-NotFound response if you try to call PUT method for non-existing row). In other words, just change attach to add, and it works for me. Also keep in mind you cannot change the field id (key) therefore first set the Id to the same as you edit. To update an existing entity, all you need to do is set the tracking state to Modified. Consider having multiple tables named (First, Second and Third). It thinks result is the book to track now and you dont want that. TableName tn context.TableNames.Attach(new TableName PKCOLUMN YOURVALUE). The fix is to tell the SQLite EF to treat GUID as TEXT (and therefore conversion is into strings, not byte) by defining BinaryGUIDfalse; in the connectionstring (or metadata, if youre using database first) like so. Provide details and share your research But avoid Asking for help, clarification, or responding to other answers. Making statements based on opinion; back them up with references or personal experience. Not the answer youre looking for Browse other questions tagged c entity-framework entity-framework-6 ef-database-first or ask your own question.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |