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SQL Anywhere 12.0.0 » SQL Anywhere Server - SQL Usage » Querying and modifying data » Full text search » Considerations when using full text search

 

Terms dropped from the text index and CONTAINS queries

Text indexes are built according to the settings defined for the text configuration object used to create the text index. A term does not appear in a text index if one or more of the following conditions are true:

  • the term is included in the stoplist

  • the term is shorter than the minimum term length (GENERIC only)

  • the term is longer than the maximum term length

The same rules apply to query strings. The dropped term can match zero or more terms at the end or beginning of the phrase. For example, suppose the term 'the' is in the stoplist:

  • If the term appears on either side of an AND, OR, or NEAR, then both the operator and the term are removed. For example, searching for 'the AND apple', 'the OR apple', or 'the NEAR apple' are equivalent to searching for 'apple'.

  • If the term appears on the right side of an AND NOT, both the AND NOT and the term are dropped. For example, searching for 'apple AND NOT the' is equivalent to searching for 'apple'.

    If the term appears on the left side of an AND NOT, the entire expression is dropped and no rows are returned. For example, 'orange and the AND NOT apple' = 'orange'

  • If the term appears in a phrase, the phrase is allowed to match with any term at the dropped term's position. For example, searching for 'feed the dog' matches 'feed the dog', 'feed my dog', 'feed any dog', and so on.

If none of the terms you are searching for are in the text index, no rows are returned. For example, suppose both 'the' and 'a' are in the stoplist. Searching for 'a OR the' returns no rows.

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