Accessing data in PowerBuilder
There are several ways to access data in the PowerBuilder development environment:
- Through one of the standard
database interfaces such as ODBC, JDBC, ADO.NET, or OLE DB - Through one of the native database interfaces
Standard database interfaces
A standard database interface communicates with a database
through a standard-compliant driver (in the case of ODBC and JDBC)
or data provider (in the case of OLE DB and ADO.NET). The standard-compliant
driver or data provider translates the abstract function calls defined
by the standard’s API into calls that are understood by
a specific database. To use a standard interface, you need to install
the standard’s API and a suitable driver or data provider.
Then, install the standard database interface you want to use to
access your DBMS by selecting the interface in the PowerBuilder Setup
program.
PowerBuilder currently supports the following standard interfaces:
- Open Database Connectivity (ODBC)
- Java Database Connectivity (JDBC)
- Microsoft’s Universal Data Access Component
OLE DB - Microsoft’s ADO.NET
Native database interfaces
A native database interface communicates with a database through
a direct connection. It communicates to a database using that database’s
native API.
To access data through one of the native database interfaces,
you must first install the appropriate database software on the
server and client workstations at your site. Then, install the native
database interface that accesses your DBMS by selecting the interface
in the PowerBuilder Setup program.
For example, if you have the appropriate Sybase Adaptive Server® Enterprise server
and client software installed, you can access the database by installing the
Adaptive Server Enterprise database interface.
Loading database interface
libraries
PowerBuilder loads the libraries used by a database interface
when it connects to the database. PowerBuilder does not automatically
free the database interface libraries when it disconnects.
Although memory use is somewhat increased by this technique
(since the loaded database interface libraries continue to be held
in memory), the technique improves performance and eliminates problems
associated with the freeing and subsequent reloading of libraries
experienced by some database connections.
If you want PowerBuilder to free database interface libraries
on disconnecting from the database (as it did prior to PowerBuilder
8), you can change its default behavior:
| To change the default behavior for |
Do this |
|---|---|
| Connections in the development environment | Select the Free Database Driver Libraries On Disconnect check box on the General tab of the System Options dialog box |
| Runtime connections | Set the FreeDBLibraries property of the Application object to TRUE on the General tab of the Properties view in the Application painter or in a script |
EAServer components This behavior cannot be controlled when components are deployed
to EAServer.