使用 @@IDENTITY / scope_identity() 时插入 2 行而不是 1 行

Question

using (SqlConnection connection = new SqlConnection(ConnectionString))
    {
        string query = "INSERT INTO SocialGroup (created_by_fbuid) VALUES (@FBUID); SELECT CAST(scope_identity() AS int)";
        SqlCommand command = new SqlCommand(query, connection);
        command.Parameters.AddWithValue("@FBUID", FBUID);

        connection.Open();
        command.ExecuteNonQuery();

        int lastID = (int)command.ExecuteScalar();

    }

Without the

SELECT CAST(scope_identity() AS int)

One row is inserted. But since I need the ID from the created row im using scope_identity. However, when I use this, 2 rows are created instead of one.

Did I miss something?

Thanks

Answer 1

The problem in the code you've posted is that you run 2 times the same query... one with ExecuteNonQuery(); and the last with (int)command.ExecuteScalar();

If you try to use only the executeScalar i think you have the result's you want....

Try and hope this helps...

If you want you can use Parameter to retrieve the Identity, like they do in this Article

Answer 2

If you would use gbn or my answer from your first question, the problem shouldn't occur.

Answer 3

Try doing

 using (SqlConnection connection = new SqlConnection(ConnectionString))     
    {         
    string query = "INSERT INTO SocialGroup (created_by_fbuid) VALUES (@FBUID);";         
    SqlCommand command = new SqlCommand(query, connection);            
    command.Parameters.AddWithValue("@FBUID", FBUID);         
     connection.Open();         
    command.ExecuteNonQuery();
     query = "SELECT CAST(scope_identity() AS int)";     
     command = new SqlCommand(query, connection);                   
    int lastID = (int)command.ExecuteScalar();      
    }