HP Intelligent Management Center Standard Software Platform - Manual (Page 734)

ODBC uses the SQL language for all transactions between Crystal Reports
and ODBC. Even if the database does not normally use SQL to create and
work with tables, the ODBC driver provided by the database (the DBMS
translation layer) must communicate with ODBC using SQL. For most users,
this feature of ODBC is transparent, but more advanced users often take
advantage of the features of the SQL language used by ODBC.
DBMS translation (ODBC data source) layer
This layer consists of one or more drivers provided by a DBMS that allow
ODBC to communicate with the database. Crystal Reports ships with several
ODBC drivers for many of the most common database formats. If you are
unsure whether you can use an ODBC driver to access the data in your
database, refer to the documentation for your DBMS application. Most DBMS
applications that run on a Windows-based platform offer an ODBC driver.
When a DBMS provides an ODBC driver, it must register the driver with
ODBC on the machine on which it has been installed. It does this by assigning
a name to the driver and recording the filename in the Odbcinst.ini file.
Usually, this step is handled automatically when the DBMS application is
installed on the system. However, your network system or DBMS application
may require that you register the ODBC driver manually with the ODBC
Setup application. For more information about registering an ODBC driver
with ODBC, refer to the documentation for your DBMS.
Once an ODBC driver is registered, you need to establish an ODBC data
source using that driver. The ODBC data source is the object that you connect
to when accessing data from Crystal Reports through ODBC. Data sources
are recorded in the Odbc.ini file. The data source keeps track of the DBMS
translation files (ODBC drivers) and, sometimes, the database itself. An
ODBC data source can specify just a database format, such as Oracle,
Sybase SQL, or MS SQL Server. Some users, however, prefer to actually
specify a particular database. In this case, the ODBC data source extends
across both the DBMS translation layer, and the database layer.
If you are using a client/server database, such as an SQL server, the ODBC
drivers communicate with the database server through the Database
Communication layer, the same layer that your database client uses to
communicate with the database server.
734 Crystal Reports 2008 SP3 User's Guide
Accessing Data Sources 26
ODBC data sources