Urgent Help using Midas with Nested Datasets

Discussion of open issues, suggestions and bugs regarding PgDAC (PostgreSQL Data Access Components) for Delphi, C++Builder, Lazarus (and FPC)
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Joined: Mon 16 Nov 2009 18:40

Urgent Help using Midas with Nested Datasets

Post by dbdriver » Mon 16 Nov 2009 18:49

I have been using midas with nested datasets for years. I am in the process of converting my application from DOA with Oracle to PGDAC woth PostgreSQL. I find no examples using PGDAC or UniDAC components with nested datasets and Midas technology. I don't have a sample application that I can send you. I could create one but it would take quite a bit of time.

The original scenario using Delphi technology resulted in creating a remote data module containing a master TQuery, TDataSource, and a detail TQuery. The TDatasource pointed to the master TQuery and the detail TQuery pointed to the TDatasource. The data was combined as a result of the parameters in the detail TQuery matching fields in the master TQuery. The master TQuery was connected to the Datasetprovider via the appropriate property.

On the client side application the TClientdataset connected to the server application via a socket connection to the remote data module. The provider of the master clientdataset was assigned the provider of the master TQuery in the remote server app. The persistent fields in the master clientdataset contained a tdatasetfield that was assigned to the dataset property of the detail clientdataset. This assignment allowed the persistent fields detail tclientdataset to be created and provided synchronization of the master and detail data.

I did a similar setup using the PGDAC components. The master tpgquery is established as the value in the tdatasource property. The mastersource of the detail tpgquery is assigned the name of the tdatasource component. The master tclientdataset in the client application is populated and the tdataset field is displayed and assigned to the property of the detail tclientdataset.

The main problem that I am having is that the parameters of the detail tclientdataset are not being passed. The value for the two integer parameters are shown as 255 and 255 in the DBMonitor program. I don't know what additional propertied to set or what to do about this problem. I have spent a large number of hours trying to figure this out. Is there number to call or any other examples to find illustrating how to make this work using your components. Please help.

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Post by Plash » Tue 17 Nov 2009 09:57

I have answered you by e-mail.

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