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ODBC

ODBC Connect : An Introduction


Introduction

It would help a lot if you were already familiar with the ODBC arcitecture and how it works on the MS-Windows o/s. If not, below is a brief explanation of ODBC.

What is ODBC Connect ?

In order to understand what 'ODBC Connect' is all about, it is first necessary to understand the basic arcitecture of Microsofts Open Database Conncetivity standard.

ODBC is a set of standard API's that enable an ODBC compliant application to obtain data from a varity of data sources which support ODBC. In order for applications to use ODBC, they must have the ODBC driver manager and a set of ODBC drivers for each data source that they wish to access, installed on their system.

Applications that want to connect to a data source, call a number of functions which are implemented in the ODBC driver manager. In MS-Window, the driver manager is ODBC.DLL. The driver manager then loads and passes on these calls to the appropiate back-end ODBC driver dll. The real work of connecting to the back end database and retriving the data is carried out by each individual driver dll.

Thus ODBC has a two tire arcitecture. An advantage of having such a design is that applications only need to interface with the ODBC driver manager. The manager takes care of loading the appropriate driver dll. Thus applications can connect to a number of different data sources without having to make any changes in their source code.

Where Does ODBC Connect fit in ?

The arcitecture described above is for applications which want to connect to data sources residing on the same machine. ODBC Connect enables applications to retrieve data spread across a TCP/IP network. In order to do this, ODBC Connect provides a .dll passthrough ODBC driver, and an ODBC API server. Applications which want to connect to a remote data source, simply connect to the 'ODBC Connect' driver and supply a remote data source name and ip address of the remote host. ODBC API calls made against the 'ODBC Connect' driver are passed on to the remote host, and are executed on the host by the API server. Data and results are passed back to the client application by the server via the 'ODBC Connect' driver dll.

In order for the server to work, it needs to have all the target driver dll that are needed to connect to a data source. These drivers are supplied with most Database products like MS-Access, Interbase etc. In addition to this, the 16-bit ODBC driver manager must also be installed on the host.

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Last Update: 11/24/96
Web Author: Shahedali Moolji
Copyright 1996 by Shahed Software Services - ALL RIGHTS RESERVED