Collating Sequences

The collating sequence defines the order in which characters are listed and records are sorted and merged. SORT-MERGE/XL allows you to specify the collating sequence as either ASCII, EBCDIC, a native language sequence, or a user-defined sequence. You can specify these sequences to be ordered in either an ascending or descending order.

The >DATA command allows you to specify either an ASCII or EBCDIC collating sequence. The >LANGUAGE command allows you to specify the collating sequence for various non-English languages if they are configured on your system. The >ALTSEQ command allows you to alter the ASCII character sequence to create a customized sequence to suit your application.

A common reason for altering the standard ASCII sequence is to have each upper case letter followed by its corresponding lower case letter, rather than listing all upper case letters first, followed by all lower case letters.

You may also want to use this feature to alter the sequence of special characters. For example, an accountant might wish to have $ appear directly after D (so that $ INVENTORY would appear immediately after Dollar INVENTORY, rather than with the special characters.) Refer to "Defining Your Own Collating Sequence" in Chapter 3 for an example on altering the sequence so that $ follows D but comes before E.

The standard types of collating sequences available to you, as well as information on user-defined collating sequences, are discussed below.

ASCII/EBCDIC

ASCII and EBCDIC are the standard collating sequences used by SORT-MERGE/XL and the data processing industry. The >ALTSEQ command allows you to modify these sequences to suit your particular application. Refer to Chapter 6 for more information on the >ALTSEQ command and collating sequences.

Native Language Collating Sequences

The >LANGUAGE command allows you to use the collating sequences for native languages other than English if they are configured on your system. The use of native language collating sequences is described in the Native Language Programmer's Guide. Refer to Chapter 6 for additional information on the >LANGUAGE command and Appendix C for a list of native language collating sequences.

User-Defined Sequences

The >ALTSEQ command allows you to alter the standard ASCII or EBCDIC collating sequence to suit your application. Refer to Chapter 6 for additional information on the >ALTSEQ command.

Ascending/ Descending Order

SORT-MERGE/XL allows you to arrange records in either an ascending or descending order. Unless you specify a descending order (for example 9, 7, 1 or Z, Y, X), SORT-MERGE/XL automatically orders the data in the ascending order (for example 1, 7, 9 or X, Y, Z). To specify a descending order use the DESC parameter of the >KEY command. Refer to Chapter 6 for additional information about the >KEY command.