Size of character sets and searching clue words
There is an inverse relationship between the number of
characters a character set supports in an index and the number of
characters in a clue word that are searched. The following table shows
how many characters each character set supports in an index and the
number of characters in a clue word that are searched for that character
set.
Character set | Max number of characters in index | Number of characters searched in clue word |
---|---|---|
ASCII | 62 | First 24 |
OVERLAP_ISO | 124 | First 20 |
ISO | 124 | First 20 |
User specified | 256 | First 16 |
For example, in an index created with a user-defined character
set, only the first 16 characters of a clue word are used in the search.
This means that any word in the index that matches the first 16 characters
of the clue word is a hit. In the following query the clue is
nonintercompatibility
:
select title from reports
where etx_contains(abstract, 'nonintercompatibility');
A
search returns both nonintercompatible
and nonintercompatibility
as
exact word matches.