如何在没有存储过程的情况下获取更新的行主键

Question

I have a situation where I need to retrieve the primary key of the updated rows in a simple update statement. I found the "RETURNING INTO" clause from Oracle, but couldn't find a way to retrieve all the primary keys from the rows that were updated, using C#, without create a stored procedure. The logic is quite simple, update some rows, get their IDs so multiple threads works on multiple sets of updated rows. Is it possible to achieve?

Answer 1

You do not need to create a stored procedure but it won't work with a simple update statement. you need at least something like this as statement:

DECLARE t_ids id_array;
BEGIN
UPDATE table
SET field1 = :value
WHERE field2 = :searchFor
RETURNING key_column BULK COLLECT INTO t_ids;

OPEN :rcursor FOR SELECT * FROM TABLE(cast(t_ids as id_array));
END;

This will return a ref cursor which you could process in c#

OracleCommand command = new OracleCommand("<the sql query above>", connection);
command.BindByName = true;

// Add the parameters for update statement
// ...

// Add the out parameter for the ref cursor
OracleParameter refCursor = new OracleParameter("rcursor", OracleDbType.RefCursor);
refCursor.Direction = ParameterDirection.ReturnValue;
command.Parameters.Add(returnCursor);

var reader = command.ExecuteReader();

OracleDataAdapter dataAdapter = new OracleDataAdapter(command);
DataTable dt = new DataTable();
dataAdapter.Fill(dt);