I've been working on a custom Data Adapter for the last day. It uses
FbDataAdapter to perform some operations, but it implements an Update()
method that works correctly with stored procedures. It can take either
a DataSet or DataTable as input. If called with a DataSet, it calls the
custom Update method with each DataTable within the DataSet. For each
row in a table, the Update method checks it to see if it has been
deleted, modified, or added. It then calls the appropriate method to
handle each case. For example, if a row has been deleted, it calls
DoDelete with the row that needs to be deleted. This method then checks
for the existence of a FbCommand object for doing deletes. It loads the
command's input parameters from the source row, then executes the
command. The method then checks for the existence of an output
parameter named "SUCCESS". If its there, then the method checks to see
if SUCCESS is 1. If so, it returns a value indicating that the
operation was successful. If SUCCESS is 0, it returns a value
indicating that the operation failed. Otherwise, it assumes that the
operation was successful and returns a value indicating success. This
is a bit of a hack, but it's the only way I could come up with to
determine whether or not the stored procedure affected any rows. This
requires that the stored procedure check for success (in the case of the
stored procedure for the delete command, it checks to make sure the
target row exists, sets the output parameter SUCCESS to 1 if does, then
performs the delete).
There is more logic in the custom adapter than I've described (basic
initialization and cleanup mainly), but I think that describes the
important pieces.
I would like to see FbDataAdapter fixed so that it works with FbCommand
objects that are stored procedures, but it may be that this isn't doable
without some modifications to the Firebird database itself.
If anyone has any questions or suggestions, please feel free to contact
me.
---Matt
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