Querying Databases From WinCC Scripts
There are two different methods for querying databases
from within WinCC
-
-
The ODK functions are tailored for use with the WinCC databases but can be
utilised to query external databases. The functions are part of the ODK
option for WinCC.
ADO is an application program interface from
Microsoft that lets a programmer access a relational or non-relational database
from both Microsoft and other database providers.
ODK Database Functions
The Open Development Kit
(ODK) option package addresses the open programming interfaces, with which data
and functions of the WinCC configuration and the WinCC runtime system can be
accessed. The interfaces are designed as C-Application Programming
Interfaces (C-APIs).
For example, ODK functions can be used
- to generate a message
- to determine the value of a tag
- to change the object properties in a screen
- to export a database table
There are a host of functions designed to access/manipulate the WinCC
databases. These functions can be used to reference other Sybase databases
however they are limiting when accessing any other databases.
top
ADO
ActiveX Data Objects (ADO) are a set of
COM (Component Object Model) objects developed by Microsoft
which can be called from WinCC scripts via the OLE Automation interface.
This is the same method used by Active Server Pages (ASP) to
publish database information on a web page.
Just as with ASP pages, the limitations of what WinCC
can do with a database are determined by the version of ADO being
utilised. For more information on ADO please refer to http://www.microsoft.com/data/ado/default.htm
top
NB: The C script examples use the OLE Automation interface in WinCC which is an unsupported interface.
If possible you should try to use the VBS script interface to access objects.
The examples have been tested by myself but please be aware that you use them at your own risk.
|
