Supporting a mixed local character set or a UTF-8 multilingual database

This topic provides guidelines for supporting a mixed local character set deployment or a UTF-8 (8-bit Unicode Transformation Format) multilingual database.

If you are working in an environment in which different computers with different local character sets connect to the same DevOps Plan application set, or you have selected the DevOps Plan UTF-8 data code page (65001) for your database set, then you must consider the following character representation issues:

Configuring the local character set

The local character set is the set of characters that can be entered or displayed in the command line shell of the application operating system. On the UNIX™ system, the local character set is controlled by the LANG environment variable.

DevOps Planprocesses data in Unicode, and its applications use the DevOps Plan data code page to write to its databases. These applications can connect to the DevOps Plan application in read/write mode even when the local character set does not match the DevOps Plan data code page.

Selecting and setting the DevOps Plan data code page of the database set

Selecting and setting the vendor database character set of your databases

You can select a UTF-8 DevOps Plan data code page for Oracle and DB2® database sets. A UTF-8 data code page allows multilingual character storage in the user database. When you select UTF-8 as the data code page, you are working in a mixed local character set deployment unless the local code page of the operating system is also UTF-8. The latter is not an option on Windows™ systems.

Coding hooks and scripts to handle characters in the DevOps Plan data code page that might not be included in the local character set

Scripts and hooks written for a mixed local character set deployment or a UTF-8 multilingual database environment must handle DevOps Plan character data that might not be included in the local character set. Those scripts and hooks must be coded to support Unicode to take full advantage of this capability in these environments.

The Designer includes a new setting: Unicode Aware. Hooks can specify whether characters in strings returned from DevOps Plan Schema API calls must be in the local character set only (RETURN_STRING_LOCAL) or can be any Unicode character (RETURN_STRING_UNICODE). Also, new API functions are available to control the return string mode. In RETURN_STRING_LOCAL mode, an API call returns an exception if the return string includes characters that cannot be represented in the local character set. In RETURN_STRING_UNICODE, an API call returns all characters without error.

To ensure that hooks and scripts handle all data in a mixed local character set or UTF-8 deployment, you must set the mode to RETURN_STRING_UNICODE and properly handle the Unicode characters that might be returned. Setting the return string mode to RETURN_STRING_UNICODE is not sufficient; you must verify that your code can handle Unicode characters correctly. The guidelines listed below are helpful, but ultimately, you must use the appropriate Unicode programming techniques for the scripting language.

If you are deploying into an environment in which local character sets do not match the DevOps Plan data code page, you must ensure that your scripts can process Unicode character data for the DevOps Plan application, set the return mode for scripts to RETURN_STRING_UNICODE. For a list of the DevOps Plan packages that support Unicode, see Package return string mode . Scripts that do not handle Unicode can run, but an error is returned if the system attempts to return to the script any character data that is not included in the local character set. These scripts continue to work as long as the data that they process is restricted to the local character set of the application or Web server.

Table 1. Package return string mode
Package Return string mode
AMWorkActivitySchedule RETURN_STRING_UNICODE
ATStateTypes RETURN_STRING_UNICODE
Attachments RETURN_STRING_UNICODE
BTStateTypes RETURN_STRING_UNICODE
Customer RETURN_STRING_UNICODE
EnhancementRequest RETURN_STRING_UNICODE
History RETURN_STRING_UNICODE
Notes® RETURN_STRING_UNICODE
Project RETURN_STRING_UNICODE
Resolution RETURN_STRING_UNICODE
When developing an application that must handle mixed character set deployments, you must address several considerations.
  • Return string mode

    The DevOps Plan applications handles all data as Unicode characters. However, schema hooks (Perl) and other DevOps Plan Schema API applications or integrations might not be coded to process Unicode characters.

    A return string mode is available to handle this problem. Hook code can be set to Unicode Aware in the Designer script editor to indicate that the script runs in the RETURN_STRING_UNICODE return string mode. (To do so, select the Unicode Aware check box). Scripts can call the SetPerlReturnStringMode method to set the return string mode to RETURN_STRING_UNICODE.

    The return string mode restricts (RETURN_STRING_LOCAL) or allows full (RETURN_STRING_UNICODE) character representation when strings are returned by the DevOps Plan Schema API for Perl.

  • Unicode support in existing hook or script code

    It is a good practice to write hooks and scripts that can process Unicode characters. RETURN_STRING_LOCAL is provided as the default return string mode so that existing hooks and scripts for DevOps Plan can run without change. Over time, you should modify existing hooks and scripts to function in RETURN_STRING_UNICODE mode, even if you currently have no need for Unicode.

    Verify that your hook or script code can process any Unicode characters. Then mark the hook code as Unicode Aware in the Designer script editor or have the external script call the SetPerlReturnStringMode method. The hook or script can then to be used in any DevOps Plan application. For example:
    1. A DevOps Plan Schema API script in Perl is running on a Windows™ Latin 1 (1252) local character set system that connects to a DevOps Plan application whose data code page is set to Shift-JIS (932).
    2. The script retrieves a field value that contains Japanese text. By default, the value is returned in the local character set of the computer that is running the Perl script (1252, in this example). Because the Shift-JIS (932) Japanese characters cannot be represented as a character in the Latin 1 code page, an exception is generated. To process this character, your application must be able to handle Unicode characters and set the return string mode to RETURN_STRING_UNICODE; the exception is not generated, and the script retrieves all the characters in the field value as Unicode characters.

    By default, an exception is thrown in step 2 when the DevOps Plan Schema API script returns with a string that includes characters outside the local character set. The exception prevents data corruption. After you review and confirm that the code can process Unicode characters, you can set the RETURN_STRING_UNICODE return string mode by using the DevOps Plan Schema API or in the script editor of the Designer. By making this change, in step 2 the DevOps Plan SchemaAPI for Perl returns the field value string as UTF8 (UNICODE) if the string contains nonlocal character set dataCharacters that cannot be represented in the local character set can then be returned to the hook or script for processing as Unicode characters.

    Hooks and scripts must use RETURN_STRING_LOCAL if they perform an operation in their scripting language (Perl or COM) that does not support processing characters that cannot be represented in the local character set. For example:
    • Using DevOps Plan data in a Perl call that does not work with Perl UTF8 strings (such as some system calls)
    • Using DevOps Plan data as a file or directory name (file and directory names must be in the local character set)
    • Writing DevOps Plan data to a file without configuring the output file to support Unicode characters
    • Sending DevOps Plan data to an integration that accepts only local character set data

    In the RETURN_STRING_LOCAL mode, operations such as running queries can be performed and the query result sets can include Unicode characters. An exception is generated only if data is extracted from that result set by a DevOps Plan Schema API method and the characters returned from the API call are not in the local character set. For example, an integration or external application can operate on a change request if the data that is passed back to the integration contains only local character set characters. The integration code must handle the exception thrown by a DevOps Plan Schema API method when the characters returned are not in the local character set. If the integration API is configured as RETURN_STRING_UNICODE, the exception is not thrown but the application must correctly handle any Unicode character that is returned. In both the RETURN_STRING_LOCAL and RETURN_STRING_UNICODE modes, exceptions are also returned to the calling integration or application if the application writes characters that cannot be represented in the DevOps Plan data code page.

  • Unicode support in packages and schemas

    Some packages or schemas are not designed to handle Unicode and nonlocal character set data. The support that each script in each package offers is indicated in the Designer script editor (the Unicode Aware check box is selected). The DefectTracking and Common schemas support Unicode. However, any schema that includes a package that does not support Unicode characters cannot be used in a mixed character set deployment. See Package return string mode .

    You can edit or add hooks that access package fields, and these hooks are considered part of the package. Those hooks inherit the default Unicode support from the package, but the Designer does not display this correct setting for the hook.

If the local character sets of all applications connected to a database set or clan match the data code page, you do not need to consider these issues.