About the Sort Order option and sort sequences

The Sort Order option (Tools > Options > Table) specifies the sort sequence (collation) for character data. The option selected defines what sort sequence is used when you sort or index records, or test sequential order, using a character field. The sort sequence is like a template against which ACL compares the first character or characters of each value in a character field when sorting, indexing, testing sequential order, or performing a quick sort. Table 1 explains the default Sort Order settings.

Table 1. Default Sort Order settings

ACL Edition

Sort Order default

Associated sort sequence

non-Unicode

System Default

(ASCII)

  • numbers, then uppercase, then lowercase

    0, 1, 2...  A, B, C...  a, b, c...

    For example, “Z” sorts before “a”.

  • Special characters occur at different points in the sequence, depending on the character.

  • Characters with diacritical marks occur at the end of the sequence and use the same uppercase before lowercase internal sequence.

Unicode

Mix Languages (UCA)

(Unicode collation algorithm)

  • numbers, then lowercase and uppercase intermixed

    0, 1, 2...  a, A, b, B, c, C...

    For example, “a” sorts before “Z”.

  • Special characters occur before numbers.

  • Characters with diacritical marks are intermixed with characters without diacritical marks.

    For example: e, E, é, É, f, F

You can change the Sort Order to a different language if it better matches the data you are analyzing. In the Unicode edition of ACL, you can also make this change on a command basis by using the ISOLOCALE parameter in the command line or a script.

In the non-Unicode edition of ACL, when you select a different language, you have the option of modifying the associated sort sequence by changing the order of the characters in the Sort Order text box. You also have the option of creating a custom sort sequence by selecting Custom in the Sort Order field and specifying a sequence, or by entering SET ORDER <TO> ‘string’ in the command line or a script and specifying a sequence. Whatever characters you specify will be sorted before all other characters, and in the sequence you specify. For example, you could specify that lowercase and uppercase letters are intermixed by entering the string aAbBcC... SET ORDER returns the sort sequence to its default setting.

The sort sequence for individual languages is derived from the byte order of each character in its character set. You can view the byte order of characters in character sets using the Windows Character Map.

Related concepts
Testing sequential order, sorting, and indexing
About testing sequential order
Sorting versus indexing
About sorting
About indexing
Sorting and indexing using computed fields


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