If special characters read from the database are not correctly represented in the ADABAS tools, mostly by a '?', and if it is not possible to enter special characters within the ADABAS tools (the terminal beeps), there can be two reasons:
- The desired national special characters are classified as non-printable characters by the operating system. The ADABAS tools only accept printable characters.
- The terminal cannot represent the national special characters because it accepts only a 7-bit code, for example.
The class of printable characters can be expanded for the ADABAS database by the national special characters by creating a file (of any name) in "$dbroot/terminfo/ chrclass" into which all desired non-printable national special characters, each in a separate line, are entered in the terminal-specific code. This can be done either by entering the characters directly via the corresponding key or by using the corresponding hexadecimal code in the notation "0x..", e.g., "0xe4". The file "german" is provided as example file. It contains all the German special characters (e.g., umlauts, etc.) in ISO 8859/1.2 code. To make this expansion known to the ADABAS database, the environment variable DBCHRCLASS has to be set to the name of the created file and then be exported.
The default value for this environment variable is the file "german".
In the second case, the tool CONTROL can be used to define a language-specific table for the mapping of codes, MAPCHARSET, in the ADABAS database in order to be able to represent at least those national special characters that are read from the ADABAS database (see the CONTROL manual). In this MAPCHAR SET, an alternative, representable notation can be assigned to each national special character.
If it is not possible, e.g., to represent the character 'ä', and in the MAPCHAR SET, the alternative notation 'ae' is assigned to the character 'ä', the character 'ä' can be mapped to the character sequence 'ae' by applying the function "mapchar" (see the Reference Manual).