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Extending HCL OneDB™Beyond standard relational database objects, HCL OneDB™ can be extended to handle specialized data types, access methods, routines, and other objects. HCL OneDB™ includes many built-in extensions that are fully integrated in the database server. HCL OneDB™ also provides DataBlade® modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for HCL OneDB™.
HCL OneDB™ extensions and DataBlade® modulesThese topics describe how to use built-in database extensions and separately installed DataBlade® modules.
Excalibur Text Search DataBlade® Module User's GuideThese topics describe the module and how to access and use its components.
ConceptsThis section describes the different types of searches you can perform with the module and characterizes how the text search engine assigns word scores and document scores.
Perform fuzzy searchesA fuzzy search is a search for text that matches your clue closely instead of exactly. Fuzzy searches can also be referred to as pattern searches. Fuzzy searches help you return results of interest even when the search terms themselves are misspelled in the documents you are searching.
Word scoring for fuzzy searchesIf you have created an index with the WORD_SUPPORT = PATTERN index parameter, the search engine considers words that match your clue approximately and that match your clue exactly. The search engine uses fuzzy logic to determine whether a pattern match is considered a hit. It assigns a word score to candidate matches based on its internal rules.

Word scoring for fuzzy searches

If you have created an index with the WORD_SUPPORT = PATTERN index parameter, the search engine considers words that match your clue approximately and that match your clue exactly. The search engine uses fuzzy logic to determine whether a pattern match is considered a hit. It assigns a word score to candidate matches based on its internal rules.

By default, only words that match your search clue by a relative measure of 70 out of 100—that have a word score of 70 or better—are considered hits. You can change the default by specifying your own value for the WORD_SCORE tuning parameter.

For example, suppose you want the text search engine to count only as hits words that match your clues by a measure of 85 or better. You would specify this condition by setting WORD_SCORE = 85 in the etx_contains() operator, as shown in the following example:

SELECT id, description FROM videos
    WHERE etx_contains ( description,
    Row('multimedia document editor' , 
        'PATTERN_TRANS & PATTERN_SUBS & WORD_SCORE = 85'));

The following sections show how you perform the types of fuzzy searches enabled by the module.