Using the DirectConnect interface
The DirectConnect interface uses Sybase’s Open Client
CT-Library (CT-Lib) API to access a database through Sybase
middleware data access products such as the DirectConnect for OS/390
component of MainFrame Connect and Open ServerConnect™.
Accessing Unicode data
PowerBuilder can connect, save, and retrieve data in both ANSI/DBCS and
Unicode databases. When character data or command text is sent to the
database, PowerBuilder sends a DBCS string if the UTF8 database parameter
is set to 0 (the default). If UTF8 is set to 1, PowerBuilder sends a
UTF-8 string.
The database server must have the UTF-8 character set installed.
See the description of the UTF-8 database parameter in the online
Help for more information.
A Unicode database is a database whose character set is set
to a Unicode format, such as UTF-8, UTF-16, UCS-2, or UCS-4. All
data must be in Unicode format, and any data saved to the database
must be converted to Unicode data implicitly or explicitly.
A database that uses ANSI (or DBCS) as its character set might
use special datatypes to store Unicode data. Columns with these
datatypes can store only Unicode data. Any
data saved into such a column must be converted to Unicode explicitly.
This conversion must be handled by the database server or client.
Connecting through the DirectConnect middleware
product
Sybase DirectConnect is a data access server that provides
a standardized middleware interface between your applications and
your enterprise data sources. Data access services to a particular
database are defined in a DirectConnect server. Since a DirectConnect
server can support multiple access services, you can access multiple
databases through a single server.
When you use the DirectConnect interface to connect to a particular
database, your connection is routed through the access service for
that database. An access service consists of a named set of configuration
properties and a specific access service library.
To access DB2 data on an IBM mainframe through a DirectConnect
server, you can use the DirectConnect interface to connect through
either a DirectConnect for MVS access service or a DirectConnect
Transaction Router Service (TRS).
TRS provides fast access to a DB2/MVS database by
using remote stored procedures. The DirectConnect interface supports
both versions of the TRS library: TRSLU62 and TRSTCP.
The DirectConnect server operates in two modes: SQL transformation and passthrough.
The DirectConnect interface for DB2/MVS uses passthrough mode,
which allows your PowerBuilder application to have direct access to
the capabilities of the DB2/MVS data source.
Connecting through the Open ServerConnect middleware
product
Sybase’s Open ServerConnect supports mainframe applications
that retrieve and update data stored on the mainframe that Sybase
client applications can execute. Client applications can connect
directly to a DB2/MVS database through an Open ServerConnect
application residing on the mainframe, eliminating the need for
an intermediate gateway like DirectConnect. (This type of connection
is also known as a gateway-less connection.)
In addition, an Open ServerConnect application presents mainframe
Remote Procedure Calls (RPCs) as database stored procedures to the
client application.
To access DB2 data on an IBM mainframe through Open ServerConnect,
you can use the DirectConnect interface to connect through Open
ServerConnect for IMS and MVS.
Selecting the type of connection
To select how PowerBuilder accesses the database, use the Choose
Gateway drop-down list on the Connection tab of the DirectConnect
Database Profile Setup dialog box and select one of the following:
- Access Service
- Gatewayless
- TRS
All the DBParm parameters defined for the DirectConnect interface
are applicable to all three connections except the following:
- HostReqOwner applies to Access
Service and Gatewayless only - Request, ShowWarnings, and SystemOwner apply to
Access Service only - UseProcSyntax applies to Gatewayless only
See the online help for the complete list of DBParm parameters
applicable to the DirectConnect interface.