This shows you the differences between two versions of the page.
— |
dev:sql:functions:score [2016/06/28 22:38] (current) |
||
---|---|---|---|
Line 1: | Line 1: | ||
+ | {{page>:top_add&nofooter&noeditbtn}} | ||
+ | <html><div align="center"><span style="color:red">DRAFT</span></div></html> | ||
+ | ====== Omnidex SQL Function: $SCORE ====== | ||
+ | {{page>:sql_bar&nofooter&noeditbtn}} | ||
+ | ===== 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> | ||
+ | |||
+ | |||
+ | {{page>:bottom_add&nofooter&noeditbtn}} |