ODBC Server Reference Manual

Architecture Overview
HP NonStop ODBC Server Reference Manual—429151-002
2-16
Message Flows
connected to two different databases. Clients 2 and 3 use different SCS processes and
are both connected to database N1_V2_S2. Note that in this example the clients all
access the same set of databases by the same names, without regard to the SCS
used (of course, if they are ODBC clients, they could access different datasource
names that lead to the same database).
Message Flows
Understanding the HP side of the NonStop ODBC Server involves recognizing what
objects are present and how they are manipulated. To that end, it will help to view the
message flows between the components. For this and following discussions, it is
important to distinguish between what the NonStop ODBC Server does and the way in
which it does it.
Suppose that the NonStop ODBC Server has been installed and the clients configured.
When a client connects, a connect or logon message (the HP term logon and the
ODBC/DBLIB term login are interchangeable) arrives at the appropriate SCS. SCS
chooses a NonStop ODBC server and passes the logon message to the server.
Figure 2-17 shows the message flow that results when a client connects.
Figure 2-16. Client Connections Through SCS
Client 1
addr = 22
db = N1_V1_S1
Client 2
addr = 22
db = N1_V1_S2
Client 3
addr = 33
db = N1_V1_S2
SCS
addr = 22
SCS
addr = 33
Database
N1_V1_S1
Database
N1_V1_S2
VST020.vsd