Types of ODBC drivers
When PowerBuilder is connected to an ODBC data source, you might
see messages from the ODBC driver that include the words single-tier or multiple–tier.
These terms refer to the two types of drivers defined by the ODBC
standard.
Single-tier driver
A single-tier ODBC driver processes both ODBC functions and SQL statements. In other words, a
single-tier driver includes the data access software required to
manage the data source file and catalog tables. An example of a
single-tier ODBC driver is the Microsoft Access driver.
Figure 2-2: Single-tier ODBC driver
Multiple-tier driver
A multiple-tier ODBC driver processes ODBC functions, but
sends SQL statements to the
database engine for processing. Unlike the single-tier driver, a
multiple-tier driver does not include the data access software required
to manage the data directly.
An example of a multiple-tier ODBC driver is the Sybase SQL Anywhere driver.
Figure 2-3: Multi-tier ODBC driver
