CTXCAT Index Parameters

These default parameters are used when you create a CTXCAT index with CREATE INDEX and do not specify any parameters in the parameter string.

The CTXCAT index supports only the index set, lexer, storage, stoplist, and wordlist parameters. Each default parameter names a system-defined preference.

Note:

Both CTXCAT and the use of CTXCAT grammar as an alternative grammar for CONTEXT queries is deprecated. Instead, Oracle recommends that you use the CONTEXT indextype, which can provide all the same functionality, except that it is not transactional. Near-transactional behavior in CONTEXT can be achieved by using SYNC(ON COMMIT) or, preferably, SYNC(EVERY [time-period]) with a short time period.

CTXCAT was introduced when indexes were typically a few megabytes in size. Modern, large indexes, can be difficult to manage with CTXCAT. The addition of index sets to CTXCAT can be achieved more effectively by the use of FILTER BY and ORDER BY columns, or SDATA, or both, in the CONTEXT indextype. CTXCAT is therefore rarely an appropriate choice. Oracle recommends that you choose the more efficient CONTEXT indextype.

Table 47 Default CTXCAT Index Parameters

Parameter Used When Default Value
DEFAULT_CTXCAT_INDEX_SET No index set specified in parameter clause of CREATE INDEX. n/a
DEFAULT_CTXCAT_STORAGE No storage preference specified in parameter clause of CREATE INDEX. CTXSYS.DEFAULT_STORAGE
DEFAULT_CTXCAT_LEXER No lexer preference specified in parameter clause of CREATE INDEX. CTXSYS.DERAULT_LEXER
DEFAULT_CTXCAT_STOPLIST No stoplist specified in parameter clause of CREATE INDEX. CTXSYS.DEFAULT_STOPLIST
DEFAULT_CTXCAT_WORDLIST

No wordlist preference specified in parameter clause of CREATE INDEX.

Note that while you can specify a wordlist preference for CTXCAT indexes, most of the attributes do not apply, because the catsearch query language does not support wildcarding, fuzzy, and stemming. The only attribute that is useful is PREFIX_INDEX for Japanese data.

CTXSYS.DEFAULT_WORDLIST

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