Updating data from grid to Oracle database.

Question

Hi
I am having some trouble updating data in a grid back to the Database. I have provided an example below. I am using the ODP.NET protocol.
The query in the proc is a simple SELECT * FROM xxxx. There are no joins (outer or inner) at all. The table xxxx has a primary key. The proc is used to fill a grid. It does this correctly by returning data to a DataTable which is then used as the data source for a grid. Then, when I make a change in the grid and press the update button, the application trys to use the da.UpdateCommand = cmdBuilder.GetUpdateCommand() statement and gets the error
"Dynamic SQL generation failed. No key information found".
Note I have tried to get around this problem by adding a key to the DataTable ... no luck.
I also tried da.MissingSchemaAction = MissingSchemaAction.AddWithKey ... no luck.
I have also tried da.FillSchema(dt, SchemaType.Mapped); ... no luck.
What am I doing wrong? ... is there a better way?
public partial class Form1 : Form
private OracleConnection a_Conn = null;
private DataTable dt = null;
private OracleDataAdapter da = null;
private OracleCommand cmd = null;
public Form1()
InitializeComponent();
private void Form1_Load(object sender, EventArgs e)
a_Conn = new OracleConnection();
a_Conn.ConnectionString = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
a_Conn.Open();
dt = new DataTable();
//SPS_TEST is a stored proc that takes no param and simply returns a dataset
cmd = new OracleCommand("SPS_TEST", a_Conn);
cmd.CommandType = CommandType.StoredProcedure;
//setup ref cursor (needed for oracle)
cmd.Parameters.Add("Cursor", OracleDbType.RefCursor, ParameterDirection.Output);
da = new OracleDataAdapter(cmd);
//da.MissingSchemaAction = MissingSchemaAction.AddWithKey;
DataColumn[] keys = new DataColumn[1];
keys[0] = dt.Columns["Name of Column with primary key in Table I have queried"];
dt.PrimaryKey = keys;
da.Fill(dt);
//grid is successfully filled at this point
fpSpread1.DataSource = dt;
private void btnUpdate_Click(object sender, EventArgs e)
OracleCommandBuilder cmdBuilder = new OracleCommandBuilder(da);
da.UpdateCommand = cmdBuilder.GetUpdateCommand();
dt.AcceptChanges();
da.Update(dt);
Rob
Edited by: user8803094 on 10-Mar-2010 19:38
Edited by: user8803094 on 10-Mar-2010 20:56

Answer 1

To the best of my knowledge, and I may be wrong here, a ref cursor does not contain any base table information. It simply contains metadata about what's in the cursor itself. The commandbuilder doesnt know what table the data came from , if it even came from an actual db table at all. As such, it's not possible for the commandbuilder to know how to generate an update statement.
You CAN update a dataset you created from a refcursor, but you have to supply your own UpdateCommand in the case, rather than using a commandbuilder.
If your ref cursor is simply a select from a table, it would probably be pretty easy to (at design time) get and note the updatecommand and parameters from a select * from the table, and then use that for the updatecommand of the dataset filled from a refcursor, as the metadata should match up. Probably not something you'd want to do on the fly though.
Hope it helps,
Corrections/comments welcome.
Greg