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dev:sql:functions:score [2016/06/28 22:38] (current)
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 +====== Omnidex SQL Function: $SCORE ======
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 +===== Description =====
 +The $SCORE function returns the "score" used to determine rank and relevancy of qualified text. Most textual applications are designed to qualify a large selection of rows and then present them in order of relevancy. A scoring algorithm ranks qualified text according to occurrence frequency, proximity, and several other factors, depending on the qualification criteria.
  
 +The $SCORE function must always be accompanied by the $CONTAINS function. Scores are only calculated when a $CONTAINS function is present in a WHERE clause predicate and therefore only available for retrieval at these times.
 +
 +The $SCORE function can be used in all SELECT statement clauses including the select list, the WHERE clause and the ORDER BY clause.
 +
 +When multiple $CONTAINS functions are present in the SELECT statement, each $CONTAINS function MUST have a unique label, and each $SCORE function MUST reference one of those labels.
 +===== Syntax =====
 +  $SCORE[(options[, label])]
 +
 +== $SCORE ==
 +
 +Required.
 +
 +== options ==
 +
 +Optional. There are currently no options for this function.
 +
 +== label ==
 +
 +Optional. A label linking this $SCORE function to a specific $CONTAINS function. Required when multiple $CONTAINS functions are present in the SELECT statement. This label is case-insensitive and may be up to 32 characters in length.
 +
 +The $SCORE function returns a value of data type FLOAT length 4.
 +===== Example =====
 +==== Example 1 ====
 +<code>
 +> select $score, title from books where $contains(content,'white rabbit') order by $score desc
 +
 +$SCORE
 +--------------------------------
 +TITLE
 +-----------------------------------------------------------------------------
 +79.050003
 +Alice's Adventures in Wonderland
 +29.570000
 +The Adventures of Huckleberry Finn
 +18.160000
 +Webster's Revised Unabridged Dictionary (1913)
 +2.860000
 +The Taming of the Shrew
 +2.860000
 +The Adventures of Tom Sawyer
 +
 +5 rows returned
 +
 +>
 +
 +This is the same statement but shows the context in which the qualified text occurred.
 +
 +> select $score, title, $context from books where $contains(content,'white rabbit') order by $score desc
 +
 +$SCORE
 +--------------------------------
 +TITLE
 +-----------------------------------------------------------------------------
 +$CONTEXT(BOOKS.CONTENT)
 +-----------------------------------------------------------------------------
 +79.050003
 +Alice's Adventures in Wonderland
 +--- daisies, when suddenly a White Rabbit with pink eyes ran --- It was the
 +>> White Rabbit returning, splendidly dressed, with --- Bill It was the
 +>> White Rabbit, trotting slowly back again, ---
 +29.570000
 +The Adventures of Huckleberry Finn
 +--- de on'y white genlman dat ever...the spunk of a rabbit. --- Is your man
 +>> white or black?" I...the spunk of a rabbit. --- the spunk of a rabbit.
 +>> I see I...up and says: "He's white." ---
 +
 +18.160000
 +Webster's Revised Unabridged Dictionary (1913)
 +--- a yellow disk and white or pinkish...ashkoko, dassy, and rock rabbit.
 +>> --- ashkoko, dassy, and rock rabbit. See Cony, and...brocade. Dambonite
 +>> (n.) A white, crystalline, sugary substance obtained ---
 +2.860000
 +The Taming of the Shrew
 +--- parsley to stuff a rabbit; and so may...gentlewoman? Such war of white
 +>> and red within her ---
 +2.860000
 +The Adventures of Tom Sawyer
 +--- a hunted and helpless rabbit look as she...her face--it was white with
 +>> terror] --"did you ---
 +
 +5 rows returned
 +
 +>
 +</code>
 + 
 +
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dev/sql/functions/score.txt ยท Last modified: 2016/06/28 22:38 (external edit)
 
 
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