ADO-DAO-Notes - DatabaseSystemsLectureNotes...

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Database Systems - Lecture Notes  Victor. Matos – CSU CIS Department References: “Mastering Access 2000” by Allison Balter, Microsoft Access-2000 Help files, personal notes on grail.cba.csuohio.edu/~matos, excerpts taken from MSDN-July  2001. The ADO 2.0 Object Model Overview ActiveX ® Data Objects (ADO) provides a common programming model for any OLE DB data source; it is essentially a collection of objects that expose the attributes and methods used to communicate with a data source. ADO uses general OLE DB providers to accesse unique features of specific data sources; it also uses native OLE DB providers, including a specific OLE DB provider that provides access to Open Database Connectivity (ODBC) drivers. Designed to replace the need for all other high-level data access methods, ADO can access relational, Indexed Sequential Access Method (ISAM), or hierarchical databases, or any type of data source—as long as there is an ODBC-compliant driver. What ADO cannot do, however, is provide remote data to the client. Once the data has been retrieved and sent to the browser, the user cannot easily manipulate it or make changes to it within the client application. Data operations—including filtering and record modifications—must take place on the server, where the actual data manipulation objects reside. How to Reference ADO 2.0 in Visual Basic & Access2000 To gain access to the ADO 2.0 objects in Visual Basic, set a reference to the appropriate ADO type library. There are two ADO type libraries. One is called ADODB and is contained in MSADO15.DLL . It appears in the References dialog box (available from the Project menu) as "Microsoft ActiveX Data Objects 2.0 Library". The other is called ADOR and is contained in MSADOR15.DLL . It appears in the References dialog as "Microsoft ActiveX Data Objects Recordset 2.0 Library". The first type library (ADODB) is the larger and more feature-rich of the two; it contains the main ADO objects and is the one you'll probably want to use in most circumstances. The second is a "lightweight" subset of the ADODB type library that supports only recordsets. You may choose to use that library instead if you plan to manipulate only recordsets. Why Use ADO? ADO is designed as an easy-to-use application level interface to Microsoft's newest and most powerful data access paradigm, OLE DB. OLE DB provides high-performance access to any data source, including relational and non-relational databases, email and file systems, text and graphics, custom business objects, and more. ADO is implemented for minimal network traffic in key Internet scenarios, and a minimal number of layers between the front-end and data source — all to provide a lightweight, high- performance interface.
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This note was uploaded on 09/07/2011 for the course MIS unknown taught by Professor Unknown during the Fall '09 term at New York Institute of Technology-Westbury.

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ADO-DAO-Notes - DatabaseSystemsLectureNotes...

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