How ADO Marshals Client-Side Recordsets

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In Chapter 13, we talked about ADO's ability to persist the contents of a Recordset object to a file. ADO creates that file in such a way that it can later reopen the file and turn the data inside back into a Recordset object.

ADO's custom marshaling routine uses similar logic. The routine examines the contents of the Recordset and packages that data in the same format used to write to a file. But instead of writing this data to a file on your hard drive, ADO passes it to the ADO libraries running in another process. These ADO libraries turn that data into a new Recordset object.

Chronologically speaking, this functionality was introduced before ADO gained the ability to save a Recordset to a file. Shortly after ADO was introduced, Microsoft's data access development team created an add-on technology originally called Advanced Data Connector (ADC). The ADC libraries could pass ADO Recordsets between local processes through COM, between machines on a network using DCOM, and between machines over the Internet through HTTP. This technology was later renamed Remote Data Service (RDS); the ability to pass Recordsets between processes using COM or DCOM is now built into ADO. We'll discuss the RDS object model as well as its ability to pass Recordset objects over the Internet in Chapter 16.



Programming ADO
Programming MicrosoftВ® ADO.NET 2.0 Core Reference
ISBN: B002ECEFQM
EAN: N/A
Year: 2000
Pages: 131
Authors: David Sceppa

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