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Comment:Add documentation for the fts4 notindexed option.
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SHA1: 968222aa1cb08ad9c694421a48db38301a29199a
User & Date: dan 2013-06-21 19:06:35.402
Context
2013-06-24
19:23
Work toward documenting the NGQP changes. (check-in: e1646aea15 user: drh tags: trunk)
2013-06-21
19:06
Add documentation for the fts4 notindexed option. (check-in: 968222aa1c user: dan tags: trunk)
08:00
Fix another minor typo in the vtable docs. (check-in: a93d66e412 user: mistachkin tags: trunk)
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Changes to pages/fts3.in.
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    to hold text in multiple languages or scripts, each with different tokenizer
    rules, and to query each language independently of the others.
    
  <tr><td>matchinfo<td> 
    When set to the value "fts3", the matchinfo option reduces the amount of
    information stored by FTS4 with the consequence that the "l" option of
    [matchinfo()] is no longer available.








  <tr><td>order<td>
    <tcl>hd_fragment fts4order {FTS4 order option}</tcl>
    ^The "order" option may be set to either "DESC" or "ASC" (in upper or
    lower case). ^If it is set to "DESC", then FTS4 stores its data in such
    a way as to optimize returning results in descending order by docid.
    ^If it is set to "ASC" (the default), then the data structures are 







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    to hold text in multiple languages or scripts, each with different tokenizer
    rules, and to query each language independently of the others.
    
  <tr><td>matchinfo<td> 
    When set to the value "fts3", the matchinfo option reduces the amount of
    information stored by FTS4 with the consequence that the "l" option of
    [matchinfo()] is no longer available.

  <tr><td>notindexed<td> 
    This option is used to specify the name of a column for which data is
    not indexed. Values stored in columns that are not indexed are not
    matched by MATCH queries. Nor are they recognized by auxilliary functions.
    A single CREATE VIRTUAL TABLE statement may have any number of notindexed 
    options.

  <tr><td>order<td>
    <tcl>hd_fragment fts4order {FTS4 order option}</tcl>
    ^The "order" option may be set to either "DESC" or "ASC" (in upper or
    lower case). ^If it is set to "DESC", then FTS4 stores its data in such
    a way as to optimize returning results in descending order by docid.
    ^If it is set to "ASC" (the default), then the data structures are 
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  Attempting to set matchinfo to anything other than "fts3" is an error.
  If this option is specified, then some of the extra information stored by
  FTS4 is omitted. This reduces the amount of disk space consumed by
  an FTS4 table until it is almost the same as the amount that would
  be used by the equivalent FTS3 table, but also means that the data
  accessed by passing the 'l' flag to the [matchinfo()] function is
  not available. 























<tcl>hd_fragment fts4prefix {FTS4 prefix option}</tcl>
<h2 tags="fts4 prefix option">The prefix= option</h2>

<p>
  ^The FTS4 prefix option causes FTS to index term prefixes of specified lengths
  in the same way that it always indexes complete terms.  ^The prefix option







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  Attempting to set matchinfo to anything other than "fts3" is an error.
  If this option is specified, then some of the extra information stored by
  FTS4 is omitted. This reduces the amount of disk space consumed by
  an FTS4 table until it is almost the same as the amount that would
  be used by the equivalent FTS3 table, but also means that the data
  accessed by passing the 'l' flag to the [matchinfo()] function is
  not available. 

<tcl>hd_fragment fts4notindexed {FTS4 notindexed option}</tcl>
<h2 tags="fts4 notindexed option">The notindexed= option</h2>

<p>
  Normally, the FTS module maintains an inverted index of all terms in
  all columns of the table. This option is used to specify the name of
  a column for which entries should not be added to the index. Multiple
  "notindexed" options may be used to specify that multiple columns should
  be omitted from the index. For example:

<codeblock>
  <i>-- Create an FTS4 table for which only the contents of columns c2 and c4</i>
  <i>-- are tokenized and added to the inverted index.</i>
  CREATE VIRTUAL TABLE t1 USING fts4(c1, c2, c3, c4, notindexed=c1, notindexed=c3);
</codeblock>

<p>
  Values stored in unindexed columns are not eligible to match MATCH 
  operators. The do not influence the results of the offsets() or matchinfo()
  auxilliary functions. Nor will the snippet() function ever return a
  snippet based on a value stored in an unindexed column.

<tcl>hd_fragment fts4prefix {FTS4 prefix option}</tcl>
<h2 tags="fts4 prefix option">The prefix= option</h2>

<p>
  ^The FTS4 prefix option causes FTS to index term prefixes of specified lengths
  in the same way that it always indexes complete terms.  ^The prefix option