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Fixed up serg's ft manual.

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jcole@ham.spaceapes.com
2000-08-29 01:21:24 +00:00
parent 438e8c7c13
commit 9edef9af3b
2 changed files with 34 additions and 27 deletions
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1
BitKeeper/etc/logging_ok
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@@ -15,3 +15,4 @@ tim@work.mysql.com
tonu@work.mysql.com
monty@donna.mysql.com
jcole@tetra.spaceapes.com
jcole@ham.spaceapes.com

60
Docs/manual.texi
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@@ -2893,15 +2893,16 @@ distributions.
@end enumerate
One goal with this is that the SQL client library should be free enough
so that it is possible to add @strong{MySQL} support in commercial products
without any license. So in this case we choose the LGPL license.
One goal is that the SQL client library should be free enough that it is
possible to add @strong{MySQL} support into commercial products
without a license. For this reason, we chose the LGPL license for the
client code.
This means that you can use @strong{MySQL} for free with any program that uses
any of the free software licences. @strong{MySQL} is also free for any end
any of the free software licenses. @strong{MySQL} is also free for any end
user for his own or company usage.
But if you use @strong{MySQL} for something important to you, you may
However, if you use @strong{MySQL} for something important to you, you may
want to help secure its development by purchasing licenses or a support
contract, @ref{Support}.
@@ -2909,7 +2910,7 @@ contract, @ref{Support}.
@subsection Copyright changes
The stable versions of @strong{MySQL} are still using a more strict
license. See the documatation for that version for more information.
license. See the documentation for that version for more information.
@node Licensing examples, Cost, Copyright, Licensing and Support
@section Example licensing situations
@@ -2922,7 +2923,7 @@ license. See the documatation for that version for more information.
This section describes some situations illustrating whether or not you
must license the @strong{MySQL} server. Generally these examples
involve providing @strong{MySQL} as a integrated part of a product.
involve providing @strong{MySQL} as an integrated part of a product.
Note that a single @strong{MySQL} license covers any number of CPUs and
@code{mysqld} servers on a machine! There is no artificial limit on the number
@@ -2947,7 +2948,7 @@ designed your application around @strong{MySQL}, then you've really made
a commercial product that requires the engine, so you need a license.
If your application does not require @strong{MySQL}, you need not obtain
a license. For example, if @strong{MySQL} just added some new optional
a license. For example, if using @strong{MySQL} just adds some new optional
features to your product (such as adding logging to a database if
@strong{MySQL} is used rather than logging to a text file), it should
fall within normal use, and a license would not be required.
@@ -13436,8 +13437,8 @@ For @code{BLOB} and @code{TEXT} columns, you must index a prefix of the
column, you cannot index the entire thing.
In @strong{MySQL} 3.23.23 or later, you can also create special
@strong{fulltext} indexes. They are used for full-text search. Only
@code{MyISAM} table type supports fulltext indexes. They can be created
@strong{FULLTEXT} indexes. They are used for full-text search. Only the
@code{MyISAM} table type supports @code{FULLTEXT} indexes. They can be created
only from @code{VARCHAR}, @code{BLOB}, and @code{TEXT} columns.
Indexing always happens over the entire column, partial indexing is not
supported. See @ref{MySQL full-text search} for details of operation.
@@ -14164,7 +14165,7 @@ mysql> select STRCMP('text', 'text');
relevance - similarity measure between the text in columns
@code{(col1,col2,...)} and the query @code{expr}. Relevance is a
positive floating point number. Zero relevance means no similarity.
For @code{MATCH ... AGAINST()} to work, a @strong{fulltext index}
For @code{MATCH ... AGAINST()} to work, a @strong{FULLTEXT} index
must be created first. @xref{CREATE TABLE, , @code{CREATE TABLE}}.
@code{MATCH ... AGAINST()} is available in @code{MySQL} 3.23.23 or later.
For details and usage examples see @xref{MySQL full-text search}.
@@ -16422,8 +16423,8 @@ When you use @code{ORDER BY} or @code{GROUP BY} with a @code{TEXT} or
@item
In @strong{MySQL} 3.23.23 or later, you can also create special
@strong{fulltext} indexes. They are used for full-text search. Only
@code{MyISAM} table type supports fulltext indexes. They can be created
@strong{FULLTEXT} indexes. They are used for full-text search. Only the
@code{MyISAM} table type supports @code{FULLTEXT} indexes. They can be created
only from @code{VARCHAR}, @code{BLOB}, and @code{TEXT} columns.
Indexing always happens over the entire column, partial indexing is not
supported. See @ref{MySQL full-text search} for details of operation.
@@ -19810,9 +19811,10 @@ table type.
For more information about how @strong{MySQL} uses indexes, see
@ref{MySQL indexes, , @strong{MySQL} indexes}.
Fulltext indexes can index only @code{VARCHAR}, @code{BLOB}, and
@code{TEXT} columns, and only in @code{MyISAM} tables. Fulltext indexes
are available from @strong{MySQL} 3.23.23. @ref{MySQL full-text search}.
@code{FULLTEXT} indexes can index only @code{VARCHAR}, @code{BLOB}, and
@code{TEXT} columns, and only in @code{MyISAM} tables. @code{FULLTEXT} indexes
are available in @strong{MySQL} 3.23.23 and later.
@ref{MySQL full-text search}.
@findex DROP INDEX
@node DROP INDEX, Comments, CREATE INDEX, Reference
@@ -34089,14 +34091,16 @@ DELAYED} threads.
Since version 3.23.23, @strong{MySQL} has support for full-text indexing
and searching. Full-text index in @strong{MySQL} is an
index of type @code{FULLTEXT}. Fulltext indexes can be created from
index of type @code{FULLTEXT}. @code{FULLTEXT} indexes can be created from
@code{VARCHAR}, @code{TEXT}, and @code{BLOB} columns at
@code{CREATE TABLE} time or added later with @code{ALTER TABLE} or
@code{CREATE INDEX}. Full-text search is performed with @code{MATCH} function.
@code{CREATE INDEX}. Full-text search is performed with the @code{MATCH}
function.
@example
mysql> CREATE TABLE t (a VARCHAR(200), b TEXT, FULLTEXT (a,b));
Query OK, 0 rows affected (0.00 sec)
mysql> INSERT INTO t VALUES
-> ('MySQL has now support', 'for full-text search'),
-> ('Full-text indexes', 'are called collections'),
@@ -34105,6 +34109,7 @@ mysql> INSERT INTO t VALUES
-> ('Full-text search in MySQL', 'implements vector space model');
Query OK, 5 rows affected (0.00 sec)
Records: 5 Duplicates: 0 Warnings: 0
mysql> SELECT * FROM t WHERE MATCH (a,b) AGAINST ('MySQL');
+---------------------------+-------------------------------+
| a | b |
@@ -34113,6 +34118,7 @@ mysql> SELECT * FROM t WHERE MATCH (a,b) AGAINST ('MySQL');
| Full-text search in MySQL | implements vector-space-model |
+---------------------------+-------------------------------+
2 rows in set (0.00 sec)
mysql> SELECT *,MATCH a,b AGAINST ('collections support') as x FROM t;
+------------------------------+-------------------------------+--------+
| a | b | x |
@@ -34126,11 +34132,11 @@ mysql> SELECT *,MATCH a,b AGAINST ('collections support') as x FROM t;
5 rows in set (0.00 sec)
@end example
Function @code{MATCH} matches a natural language query @code{AGAINST} a
The function @code{MATCH} matches a natural language query @code{AGAINST} a
text collection (which is simply the columns that are covered
by fulltext index). For every row in a table it returns relevance -
similarity measure between the text in that row (in the columns, that
are part of the collection) and the query. When it used in a
by a @strong{FULLTEXT} index). For every row in a table it returns
relevance - similarity measure between the text in that row (in the columns
that are part of the collection) and the query. When it is used in a
@code{WHERE} clause (see example above) the rows returned are
automatically sorted with relevance decreasing. Relevance is a non-
negative floating point number. Zero relevance means no similarity.
@@ -34138,13 +34144,13 @@ Relevance is computed based on number of words in the row and number of
unique words in that row, total number of words in the collection,
number of documents (rows), that contain a particular word, etc.
MySQL uses very simple parser to split text into words. "Word" is
MySQL uses a very simple parser to split text into words. A "word" is
any sequence of letters, numbers, @code{'}, and @code{_}. Any "word"
that is present in stopword list or just too short (3 characters or less)
is ignored.
that is present in the stopword list or just too short (3 characters
or less) is ignored.
Every correct word in the collection and in the query is weighted,
according to their significance in the query or collection. This way, a
according to its significance in the query or collection. This way, a
word that is present in many documents will have lower weight (and may
even have a zero weight), because it has lower semantic value in this
particular collection. Otherwise, if the word is rare, it will receive a
@@ -34152,7 +34158,7 @@ higher weight. Weights of the words are then combined to compute the
relevance.
Such a technique works best with big collections (in fact, it was
carefully tuned up this way). For very small tables word distribution
carefully tuned up this way). For very small tables, word distribution
does not reflect adequately their semantical value, and this model
may sometimes produce bizarre results.