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DataServer for Microsoft SQL Server
Initial Programming Considerations : Database design issues : Code pages

Code pages

Flexibility in managing code pages, also called character sets, is critical for international applications. When you access a MS SQL Server data source through the DataServer, the DataServer retrieves character data as determined by the code page that the data source uses. For OpenEdge databases, the default code page is iso8859-1; however, the OpenEdge model allows you to designate code pages for the data source and for the client.
The following figure shows a possible configuration of code pages for the DataServer components and processes.
Figure 9. DataServer processes and code pages
In the configuration shown in the figure above, all components use the same code page. The OpenEdge iso8859-1 code page is a subset of the iso_1 code page used by the default installation of MS SQL Server. For information on setting character sets for your data source, see the administration guide supplied by the vendor. On the OpenEdge side, if the client and the schema holder use different code pages, a conversion takes place between them.
In order for DataServer applications to manipulate data from a MS SQL Server data source accurately, you must specify the correct code page and collation in the schema holder. For OpenEdge applications accessing the DataServer, the schema holder identifies the code page of the character data. The DataServer sends the data source name for the code page to the data source to indicate the character set for the data that the data source returns.
Be sure to set the code page in the schema holder to match a code page that the MS SQL Server data source supports. To minimize the number of translations, specify the default code page that the data source uses. If OpenEdge does not support the code page, you can specify instead a compatible code page that is available for your data source. The directory %DLC%\prolang\convmap contains conversion tables for all of the code pages that OpenEdge supports. Check to see whether any of them match your code page.
The default code page setting in the schema holder is iso8859-1. You can specify a different code page for the schema holder at the following times:
*When you create the DataServer schema for the MS SQL Server data source.
*When you load a new schema with a specified code page into an existing schema holder. In this case, the newly loaded schema's code page overrides the schema holder's original code page.
Note: It is possible to change the code page at other times. However, because changing the code page does not affect the data already in the database, writing new data to your database using a different code page can corrupt the data in your database. You cannot use the PROUTIL utility to change the code page used by the DataServer.
Keep in mind that your MS SQL Server software configuration might have local requirements for defining the proper language interface between the ODBC drivers and the data source. See your Microsoft SQL Server database documentation for details.
* Client code page
* Code page, collation, and case conflicts