MX 2.x)

ODBC/MX Client Overview

HP NonStop Open System Services ODBC/MX Client Driver—544990-002

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Data Source Configuration

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If an ODBC client tries to connect to a data source in the NonStop system, and the

client data source name and the NonStop system data source name do not match

(including the case), the Association Server connects the ODBC client to

TDM_Default_DataSource.

Data Source Configuration

In OSS ODBC/MX Client Driver, the ODBCDSN file is used to specify the configuration

details of data sources. The ODBCDSN file is an edit file that is available at the

$SYSTEM.SYSTEM location. The default data source configuration file must be

updated with the proper values before usage. For more information on data source

configuration, see Configuring Data Sources on page 2-2.

The OSS ODBC/MX Client Driver accesses the ODBCDSN file to configure the data

source at the time of initial connection establishment (using the SQLConnect()

function) between the OSS ODBC/MX Client Driver and the data source. The OSS

ODBC/MX Driver Manager is a part of the OSS ODBC/MX Client Driver that accesses

the ODBCDSN file.

The OSS ODBC/MX Client Driver initially parses through the ODBCDSN file and

fetches the required data source configuration details. If an application requested data

source is not available, default data source information specified in the ODBCDSN file

is fetched. The OSS ODBC/MX Client Driver contacts the Association Server to

connect to the data source.

OSS ODBC/MX Client Driver Architecture

The NonStop OSS ODBC/MX Client Driver is functionally equivalent to the Windows

ODBC/ MX Driver, with few unsupported features.

The OSS ODBC/MX Client Driver is thread-safe. This feature is introduced in the

SQL/MX 2.3.4 release.

The OSS ODBC/MX Client Driver can be used with multi-threaded C/C++ programs,

which use the T1248 standard POSIX thread library. During the ODBC call execution,

the OSS ODBC/MX Client Driver is thread-blocking and not

process-blocking.

Figure 1-1 shows the architecture of OSS ODBC/MX Client Driver.

Note. If an ODBC client tries to connect to a server data source that is stopped, MXCS

rejects the connection.