Entity Framework does not add new row to database

Question

Adding data to database on MVC 4.5 using Entity Framework. I am using the code below to add data to the the table a a new row the candidate may contain, will not be adding the entire row. I would like to know why this is not working, I get no compile or runtime errors.

var subject = db.subjects_tbl;

var sub = subject.CreateObject();
sub.subject_title = model.subject_title;
sub.language_Id = model.language_Id;

db.subjects_tbl.Attach(sub);

db.ObjectStateManager.ChangeObjectState(sub, EntityState.Added);

db.SaveChanges();

I re-worded your question to focus on Entity Framework instead of MVC, is this what you intended? — Matthew
– Matthew, Commented May 14, 2015 at 14:24

Henk Holterman · Accepted Answer · 2015-05-14 14:30:32Z

3

You don't need the Attach() and ChangeObjectState(), but you do need to Add() an entity to its DbSet.

var sub = subject.CreateObject();
sub.subject_title = model.subject_title;
sub.language_Id = model.language_Id;

//db.subjects_tbl.Attach(sub);
//db.ObjectStateManager.ChangeObjectState(sub, EntityState.Added);
db.subjects_tbl.Add(sub);

db.SaveChanges();

From the DbSet.Attach page:

SaveChanges will therefore not attempt to insert an attached entity into the database because it is assumed to already be there.

edited May 14, 2015 at 14:30

answered May 14, 2015 at 14:24

Henk Holterman

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7 Comments

user3636426 Over a year ago

waht is the assebly reference to use the add method

user3636426 Over a year ago

does not contain a definition for 'add' and no extension method 'add' accepting a first argument of type could be found (are you missing a using directive or an assembly reference?). this is the message i am getting

user3636426 Over a year ago

private cisielearningEntities db = new cisielearningEntities();

user3636426 Over a year ago

subjec us type subject_tbl

user3636426 Over a year ago

the version of entity framework that i am using i 4.5

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Alexey Nis · Accepted Answer · 2015-05-14 14:51:09Z

1

Also you can change EntryState of a Subject to Created, Updated or Deleted using DbContext (your db object, I guess).

var subject = db.subjects_tbl;

var sub = subject.CreateObject();
sub.subject_title = model.subject_title;
sub.language_Id = model.language_Id;

db.Entry(sub).State = EntityState.Added;

db.SaveChanges();

MSDN For more details.

answered May 14, 2015 at 14:51

Alexey Nis

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2 Comments

user3636426 Over a year ago

does not contain a definition for 'Entry' and no extension method 'Entry' accepting a first argument of type could be found (are you missing a using directive or an assembly reference?). this is the error i am getting any ideas why.

Alexey Nis Over a year ago

1. What type of db object? 2. Do you have using System.Data.Entity?

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