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dtSearch Text Retrieval Engine Programmer's Reference
Options Overview

Overview of option settings

Language
Options API
C/C++
DOptions or dtsOptions
.NET (C#, VB.NET)
Java
COM (Visual Basic, ASP)
IOptions (Options) object

 

Option settings are maintained separately for each thread, so changes to options in one thread will not affect a job in progress on another thread. When a new thread is started, it will inherit the most recent option settings from other threads in the process. 

Option settings cannot be changed from within a callback function such as DataSource.GetNextDoc.

BinaryFiles

Binary files are files that are not in a format that dtSearch recognizes and that do not appear to be plain text files. See the BinaryFiles enumeration for values.

BinaryFilterTextChars

If BinaryFiles is set to dtsoFilterBinary, the dtSearch Engine will look for sequences of text characters in binary files and index them as text. By default, only the letters a-z and the digits 0-9 are treated as text characters. To change this, list the characters to be treated as text in BinaryFilterTextChars.

Hyphens

Determines how hyphens are handled in text.

AlphabetFile

Name of dtSearch alphabet file to use when parsing text into words. The alphabet file determines which characters are letters and what the rules are for handling capitalization and punctuation. If blank, a default alphabet will be created based on information supplied by Windows.

IndexNumbers

If TRUE, numbers will be indexed.

NoiseWordFile

Name of noise word list to use when creating index. Words listed in this file will be ignored when building indexes and are not searchable. (A noise word list is built into the index when it is created, so changing the NoiseWordFile will have no effect unless you create an index.)

StemmingRulesFile

Name of the file containing stemming rules to use when searching. See the stemming.dat file supplied with the dtSearch Engine for instructions on customizing these rules.

MaxWordsToRetrieve

Maximum number of words that can be matched in a search. This can be any value from 16 to 256k. The default is 64k. If a search matches more unique words than the maxWordsToRetrieve limit, the error code dtsErMaxWords (137) will be returned. This can also be set in each search through a property of SearchJob.

MaxStoredFieldSize

Maximum size of a single stored field. Stored fields are field data collected during indexing that is returned in search results.

TitleSize

By default, the dtSearch Engine collects the first 80 characters of text from a file for the title associated with each document. Use this option to change the number of characters stored, up to a maximum of 512.

MaxWordLength

Words longer than the maxWordLength will be truncated when indexing. The default maxWordLength is 32. The maximum value is 128.

SegmentationRulesFile

Name of the file containing file segmentation rules, which tell the dtSearch Engine to break up certain text files into logical subdocuments based on markers in the index. See the File Segmentation Rules topic in the dtSearch Desktop help file for information on this setting.

TextFieldsFile

Name of the file containing rules for extraction of field data from text files based on markers in the next. See the Define Text Fields topic in the dtSearch Desktop help file for information on this setting.

UserThesaurusFile

Name of the file containing a user thesaurus created with dtSearch Desktop.

UpdateFiles

Set updateFiles to TRUE to tell the dtSearch Engine to re-read all setting files, even if a filename has not changed, because the contents of the file may have been updated. For example, if you change the contents of the stemming rules file while the dtSearch Engine is running but have not changed the name of the file, use this flag to tell the dtSearch Engine to update its internal copy of the stemming rules even though the StemmingRulesFile setting has not changed. 

The dtSearch Engine does not actually read the files until they are needed for indexing or searching.

LzwEnableCode

In dtSearch Engine versions prior to 6.4, LZW decompression in the dtSearch Engine was locked with an access code due to patent issues. Since the expiration of the LZW patent in July 2004, LZW decompression is no longer locked, and this option setting has no effect.

PrivateDir

A directory that the dtSearch Engine can use to store temporary files created during indexing. The PrivateDir must be unique for each concurrent user of the Engine. If the PrivateDir is blank, no directory will be reserved for temporary files, and the Windows TEMP folder will be used.

HomeDir

Directory where the dtSearch Engine and support files are located. This may be a shared, read-only network directory.

BooleanConnectors

Replaces the default connectors used in search requests.

FileTypeTableFile

Name of the file containing a table of filename patterns for file formats that dtSearch cannot detect automatically, such as older versions of WordStar. See the File Types topic in the dtSearch Desktop help file for information on this setting.

FieldFlags

FieldFlags values that determine how dtSearch handles document metadata

MacroChar @; FuzzyChar %; PhonicChar #; StemmingChar ~; SynonymChar &; WeightChar :; MatchDigitChar =

Use these option settings to change the default values (shown above) of the special characters used to invoke search features in a search request. See Search Features for more information on the meaning of each special character. The following special characters in search requests cannot be redefined: * ? ( ) " 

Notes: 

(1) The prefix used to identify regular expressions is based on a doubling of the phonicChar (##). 

(2) The mark used to add a field name in front of a word is based on a doubling of the weightChar (::) 

(3) The mark used to express ranges is a doubling of the stemmingChar (~~). 

(4) Characters must be single-byte punctuation characters.

TextFlags

TextFlags values that control text-processing options.

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