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I'm using Oracle provider for Entity framework (beta), and I'm facing a problem.
Our tables have Id columns, which are set to be Identity in StoreGeneratedPattern. I thought that EF will automatically do "underlying works", such as create sequences, and get new identity for each record I add to the table. But when I run code to add a new record, such as:
var comment = new Comment
{
ComplaintId = _currentComplaintId,
Content = CommentContent.Text,
CreatedBy = CurrentUser.UserID,
CreatedDate = DateTime.Now
};
context.Comments.AddObject(comment);
context.SaveChanges();
an Exception still throws, which is
{"ORA-00001: unique constraint (ADMINMGR.CONSTRAINT_COMMENT) violated"}
(CONSTRAINT_COMMENT is the constrain requires that comment identity must be unique.
How do I solve this?
Thank you very much!
897
Yes. See this step by step tutorial of Entity Framework, LINQ, and Model-First for the Oracle database (11G), and using Visual Studio 2010 with .
An INTEGER, LONG, or NUMBER column in a table can be defined as an identity column. The system can automatically generate values for the identity column using a sequence generator. See Sequence Generator section. A value for an identity column is generated during an INSERT, UPSERT, or UPDATE statement.
EF execute each INSERT command followed by SELECT scope_identity() statement. SCOPE_IDENTITY returns the last identity value inserted into an identity column in the same scope. The above example will execute the following SQL in the database. WHERE @@ROWCOUNT = 1 AND [StudentID] = scope_identity();
Oracle 12c has resolved it
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int SomeNumber { get; set; }
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