stopwords index parameter

Usage

You can create a stopword list for all fields or customized stopword lists for specific fields. Any words that are listed before any field names become the default stopword list, which is used for all fields not explicitly listed. All words that are listed after a field name and before the next field name are stopwords for the preceding field only. If a field is listed without any words following it, that field does not have a stopword list.

You can specify the list of stopwords in a table column or in a file. The file or table must be readable by the user who is creating the index. Separate the field name and stopword pairs in the file or table by commas, white spaces, new lines, or a combination of those separators. The file or table becomes read-only when the index is created. If you want to add or change stopword assignments, you must drop and re-create the index.

Examples

Example 1: Input stopwords as inline comma-separated words

Inline comma-separated words are useful when you have only a few stopwords. The following example prevents searching the words "am,", "be," and "are":

stopwords="(am,be,are)"

The following example shows how to create a bts index with an inline comma-separated customized stopword list:

CREATE INDEX books_bts ON books(book_data bts_lvarchar_ops) 
USING bts(stopwords="(am,be,are)") IN bts_sbspace;

Example 2: Input stopwords from a file or a table column

The following example shows the contents of a stopword file where stopwords are separated by commas, white spaces, and new lines:

avec, et
mais pour  

The following example shows how to create a bts index with a customized stopword list in a file:

CREATE INDEX books_bts ON books(book_data bts_lvarchar_ops) 
USING bts(stopwords="file:/docs/stopwords.txt") IN bts_sbspace;

The following example shows how to create a bts index with a customized stopword list in a table column:

CREATE INDEX books_bts ON books(book_data bts_lvarchar_ops) 
USING bts(stopwords="table:mytable.mycolumn") IN bts_sbspace;

Example 3: Create stopword lists for specific fields

The following example creates a stopword list of am, be, and are for all fields except the fields author and title, which have their own stopwords, and the field edition, which does not have any stopwords.

CREATE INDEX books_bts ON books(book_data bts_lvarchar_ops)
USING bts(stopwords=
    "(am,be,are, 
      author:mrs,mr,ms, 
      title:the,an,a,or,
      edition:)"
       ) 
IN bts_sbspace;