Overview of ODBC
What is ODBC?
Open Database Connectivity (ODBC) is a standard method of accessing data across diverse database management systems. It ensures that applications don't need to use different proprietary languages for different database.
Open Client is a Sybase proprietary connection method that only works with Sybase databases. Net8 is an Oracle connection protocol that only works with Oracle databases. If an application needs to access both database systems, the programmer can either write code in two different languages, or use the common ODBC calls.
What is an ODBC driver?
An ODBC driver is software that conforms to the ODBC standard. Applications "talk to" the ODBC driver that sits as a layer between the application and the database system. The ODBC driver accepts the common ODBC calls from the application and "talks to" the database software.
When your application uses ODBC to interface with a Sybase database, there must be an appropriate ODBC driver installed on the host machine.
What is ODBC Manager?
On the Windows platform, the ODBC Manager is installed as standard. This piece of software manages the different ODBC drivers installed on the host machine. When the same application accesses both Sybase and Oracle database, the ODBC Manager ensures that the different ODBC drivers are used for each connection.
Origins of ODBC
The major database vendors formed the SQL Access Group in the early nineties to agree on common standards for interfacing with SQL databases. Microsoft used the SQL Access Group protocols to create ODBC and released ODBC 1.0 in 1992. There have been some competing protocols since then, but ODBC has become the commonly-adopted industry standard.
ODBC and Performance
Because ODBC is an extra layer between the application and the database software, there may be a performance penalty. Early versions of Sybase ODBC drivers communicated with the database through the Sybase client libraries. This actually put two layers between the application and the database, and could be a significant performance hit.
Recent ODBC drivers from both Sybase and DataDirect are using what's called "wire protocol" drivers. Wire protocols don't use the Sybase client library, eliminating that performance overhead.
Submitted: 10 Nov 2006
Author: Caroline Walsh, Five Salmon Consultancy
(c) Five Salmon 2006