更新没有主键的表的一组行

Question

I want to update set of rows using ODP.net. I want to get list of employees based on increasing asscending order of PRIORITY and update PRIORITY column with value 1 and increment by 1. I tried below approach and it gives error "Dynamic SQL generation failed. No key information found"

StrQuery = "SELECT * FROM EMPLOYEE WHERE DEPT ='" + dept + "' ORDER BY PRIORITY";
DataTable dt = new DataTable();
OracleDataAdapter da = new OracleDataAdapter();
da.SelectCommand = new OracleCommand(StrQuery, ora);
OracleCommandBuilder cb = new OracleCommandBuilder(da);
da.Fill(dt);
intNpriority = 1;
foreach (DataRow row in dt.Rows)
{
    row["PRIORITY"] = intNpriority;
    intNpriority = intNpriority + 1;
}
da.UpdateCommand = cb.GetUpdateCommand();
da.Update(dt);

The table has no primary key and i cannot add one now. Can i add custom update query and how? Is there anyalternative way to acheive same?

table strucure:

column name   |  (data type)
Employee_name |  (varchar2)
dept          |  (varchar2)
PRIORITY      | (NUMBER)

Answer 1

I've spent two days to find some way to workaround. Lucky that I could get it done. The idea is to add a dump primary key in the DataTable, this new dump column does not affect the real database table. Here's my code sample

Dim currentRow = m_DataTable.Rows(m_RowPosition) Dim tmpRows() As DataRow = {currentRow}

        Dim cmdBuilder As OracleCommandBuilder = New OracleCommandBuilder(m_Adapter)
        
        **If m_DataTable.PrimaryKey.Count = 0 Then
            m_DataTable.Columns.Add(New DataColumn("_ID_", System.Type.GetType("System.String")))
            m_DataTable.Columns("_ID_").Unique = True
        End If**

        m_Adapter.Update(tmpRows)

Note: The currentRow is the row is being edited . Please consider carefully to apply this tip because it might update all data of table. It's suitable for case your table has only one row ( some kind of configuration data )