Thesaurus Files

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Thesaurus Files

Steve Jones - SSC Editor

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October 9, 2008 at 9:21 pm

#194477

Comments posted to this topic are about the item Thesaurus Files

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Ron McCullough SSC Guru Points: 63877 More actions · Answer 1

From BOL 2008 Thesaurus Configuration

ms-help://MS.SQLCC.v10/MS.SQLSVR.v10.en/s10de_1devconc/html/3ef96a63-8a52-45be-9a1f-265bff400e54.htm

You can define two forms of synonyms, expansion sets and replacement sets. By developing a thesaurus tailored to your full-text data, you can effectively broaden the scope of full-text queries on that data.

Expansion set
An expansion set contains a group of synonyms such as "writer", "author", and "journalist" that are substituted for one another by a full-text query. Queries that contain a match for any synonym in an expansion set are expanded to include every other synonym in the expansion set.

Some one explain to me how this supports the supposed correct answer.

If everything seems to be going well, you have obviously overlooked something.

Ron

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Before posting a performance problem please read[/url]

patriwala Old Hand Points: 303 More actions · Answer 2

A thesaurus query uses both a language-specific thesaurus and the global thesaurus. First, the query looks up the language-specific file and loads it for processing (unless it is already loaded). The query is expanded to include the language-specific synonyms specified by the expansion set and replacement set rules in the thesaurus file. These steps are then repeated for the global thesaurus. However, if a term is already part of a match in the language specific thesaurus file, the term is ineligible for matching in the global thesaurus.

reference site

http://msdn.microsoft.com/en-us/library/ms142491.aspx

Mike C SSC-Insane Points: 23224 More actions · Answer 3

bitbucket (10/10/2008)
From BOL 2008 Thesaurus Configuration
ms-help://MS.SQLCC.v10/MS.SQLSVR.v10.en/s10de_1devconc/html/3ef96a63-8a52-45be-9a1f-265bff400e54.htm
You can define two forms of synonyms, expansion sets and replacement sets. By developing a thesaurus tailored to your full-text data, you can effectively broaden the scope of full-text queries on that data.
Expansion set
An expansion set contains a group of synonyms such as "writer", "author", and "journalist" that are substituted for one another by a full-text query. Queries that contain a match for any synonym in an expansion set are expanded to include every other synonym in the expansion set.
Some one explain to me how this supports the supposed correct answer.

The key word here is "recursively". Once a match is found in the thesaurus SQL Server stops searching for further matches. For instance, consider a thesaurus that defines the following expansion set:

fl

fla

florida

</expansion>

And this expansion set:

fl

fluid

</expansion>

A search for "fl" will search for "fl", "fla", and "florida". FTS will stop at the first expansion set and won't continue to expand "fl" to "fluid" as defined by the second expansion set.

As for the recursive part, consider a search for "fla". Again FTS will expand this to search for "fl", "fla", and "florida". It will not recursively search for more expansion or replacement rules, so "fl" will not be expanded out to "fluid" this time either.

Ron McCullough SSC Guru Points: 63877 More actions · Answer 4

Mike C.

Thanks for that detailed explanation. Explains a lot and I will have to remember that when creating a thesaurus.

Again thank you.

If everything seems to be going well, you have obviously overlooked something.

Ron

Please help us, help you -before posting a question please read[/url]
Before posting a performance problem please read[/url]

Anipaul SSC-Insane Points: 24681 More actions · Answer 5

Anipaul

SSC-Insane

Points: 24681

October 13, 2008 at 4:22 am

#884053

Mike great explaination

Oleg-461731 SSChasing Mays Points: 619 More actions · Answer 6

In my opinon the great disadvantage of MS thesaurus implementaion is that sql server does not use forms of thesaurus words.

If user wants to have "full functional synonym" he should add expansion for all forms of words.

For example:

Tabke contains records with forms of word "source", I added synonyms

_source

_lake

_river

_drink

In this case if I search word "rivers" or "drank" I never find these records(!).

But if I added yet expansion:

_drink

_drank

_drunk

_drinking

_drinker

_drinkeress

_drinkable

In this case I search "drank" and I can find records with "source".

Regards.

Mike C SSC-Insane Points: 23224 More actions · Answer 7

Hi Oleg,

You could use the sys.dm_fts_parser to retrieve the expansion sets from SQL Server and use that to recreate a query string that includes all your inflectional and thesaurus word forms. I haven't tested the performance of sys.dm_fts_parser (since I usually use it for one-off testing in Management Studio), so there might be performance implications.

Thanks

Mike C