Manual

Chapter 4. Deploying applications with DB2 157
Once the connection succeeds, the application outputs a message to the screen.
Then it releases the connection handle and environment handle in sequence.
Figure 4-2 shows the logic in our sample application.
Figure 4-2 logic of sample application
Note: A DSN-less connection means connecting to a data source without a
system level DSN or file DSN created. The connection string is used instead
of a system level DSN or file DSN to keep the data source connectivity
information. The CLI function SQLConnect() does not support a connection
string. That is why we use SQLDriverConnect() in our sample application.
An introduction to the three types of connection functions in CLI programming
can be found at the DB2 Information center:
http://publib.boulder.ibm.com/infocenter/db2luw/v9r5/topic/com.ibm.db2.luw.a
pdv.cli.doc/doc/t0004608.html
Allocate an environment Handle
SQLAllocHandle ()
Allocate an connection Handle
SQLAllocHandle ()
Make a connection to database
SQLDriverConnect ()
Obtain diagnostic information
SQLGetDiagRec ()
Disconnect from database
SQLDisconnect ()
Free the database handle
SQLFreeHandle ()
Free the environment handle
SQLFreeHandle ()
Application Start
Read connection info from cmd
Application End
Output error message
printf ()