OpenEdge Data Management: DataServer for Microsoft SQL Server

Initial Programming Considerations
2–6
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
The Internal Code Page (-cpinternal) startup parameter determines the code page that the
OpenEdge client uses when it manipulates data in memory. If the OpenEdge client uses a
different code page from the code page set in the schema holder, the DataServer translates
between the two code pages, so you must verify that the convmap.cp file contains a conversion
table for the client and the code page setting in the schema holder. Suppose, for example, that
you set the schema holder to code page ibm850 and the client uses code page iso8859–1. The
convmap.cp file must include a table that converts from ibm850 to iso8859–1 and from
iso8859–1 to ibm850. If convmap.cp does not include the appropriate table, you can define your
own conversion table.
OpenEdge also allows you to define your own collation tables; however, customized collation
tables only take effect after data source collation when you use the DataServer to access a MS
SQL Server data source. The data source collation tables, not the OpenEdge collation tables,
have first priority when you perform comparisons and sorts. After performing comparisons and
sorts, the OpenEdge client may sort out records that do not conform to the requirements of your
customized collation tables.