对MYSQL进行全文检索的PHP类库
正在研究中，如果要看这个程序的详细说明和演示，请到这个地方看，真的很爽： http://steven.haryan.to/php/KwIndex.html
注意，只能在linux,unix下用。
< ?php
$debug = 0;
if($debug) require “Dumper.lib”; //这个全文检索需要的库文件，你有吗？
function _debug() {
global $debug;
$args = func_get_args();
if (!$debug) return;
echo ”
debug: ", htmlentities(join("", $args)), "
\n";
}
class KwIndex {
# CONSTRUCTOR
#############
function KwIndex($args) {
# check for argument type
if (!is_array(&$args))
die(“KwIndex: constructor: syntax: KwIndex(array \$args)”);
# check for unknown arguments
$known_arguments = array_flip(array(
“linkid”, “db_name”, “hostname”, “username”, “password”,
“index_name”, “wordlist_cardinality”, “doclist_cardinality”,
“stoplist_cardinality”, “vectorlist_cardinality”,
“max_word_length”, “use_persistent_connection”));
while(list($k,$v) = each($args))
if (!isset($known_arguments[$k]))
die(“KwIndex: constructor: unknown argument `$k’”);
# required for required arguments
if (!isset($args["db_name"]))
die(“KwIndex: constructor: You must specify ‘db_name’”);
if (!isset($args["linkid"]) &&
(!isset($args["hostname"]) || !isset($args["username"]) ||
!isset($args["password"])))
die(“KwIndex: constructor: You must either specify ‘linkid’ or “.
“arguments to mysql_connect (‘hostname’, ‘username’, and “.
“‘password’)”);
# supply default values for optional arguments
if (!isset($args["index_name"]))
$args["index_name"] = “kwindex”;
if (!isset($args["wordlist_cardinality"]))
$args["wordlist_cardinality"] = 100000;
if (!isset($args["stoplist_cardinality"]))
$args["stoplist_cardinality"] = 10000;
if (!isset($args["vectorlist_cardinality"]))
$args["vectorlist_cardinality"] = 100000000;
if (!isset($args["doclist_cardinality"]))
$args["doclist_cardinality"] = 1000000;
if (!isset($args["max_word_length"]))
$args["max_word_length"] = 32;
if (!isset($args["use_persistent_connection"]))
$args["use_persistent_connection"] = 1;
# set object attributes
$this->db_name = $args["db_name"];
$this->index_name = $args["index_name"];
$this->wordlist_cardinality = $args["wordlist_cardinality"];
$this->stoplist_cardinality = $args["stoplist_cardinality"];
$this->vectorlist_cardinality = $args["vectorlist_cardinality"];
$this->doclist_cardinality = $args["doclist_cardinality"];
$this->max_word_length = $args["max_word_length"];
if (!isset($args["linkid"])) {
if ($args["use_persistent_connection"]) {
$linkid = mysql_pconnect($args["hostname"], $args["username"],
$args["password"]);
} else {
$linkid = mysql_connect($args["hostname"], $args["username"],
$args["password"]);
}
if (!$linkid)
die(“KwIndex: constructor: Can’t connect to database: “.
mysql_error());
} else {
$linkid = $args["linkid"];
}
$this->linkid = $linkid;
$idx = $this->index_name;
if (!mysql_select_db($this->db_name, $linkid))
die(“KwIndex: constructor: Can’t select DB: “.
mysql_error($linkid));
if (!$this->_index_exists()) $this->_create_index();
# load stoplist as keys of array
$this->stoplist = array();
if (!($res = mysql_query(“SELECT word FROM ${idx}_stoplist”,
$linkid)))
die(“KwIndex: constructor: Can’t load stoplist: “.
mysql_error($linkid));
while($row = mysql_fetch_row($res)) {
$this->stoplist[ strtolower($row[0]) ] = 1;
}
} // constructor
# PUBLIC METHODS
################
function &document_sub($doc_ids) {
die(“KwIndex: document_sub: this method must be overriden”);
}
function add_document($doc_ids) {
if (!is_array(&$doc_ids))
die(“KwIndex: syntax: add_document(array \$doc_ids)”);
if (!sizeof(&$doc_ids)) return 1;
$wordlist = array();
# structure: ( ‘word1′ => [ [doc_id,freq], … ], … )
$doclist = array();
# format: ( doc_id => n, … ); # n = number of words in document
# retrieve documents
####################
$docs = $this->document_sub(&$doc_ids);
if(!is_array(&$docs))
die(“KwIndex: add_document: “.
“‘document_sub’ does not return an array”);
if (sizeof(&$doc_ids) < sizeof(&$docs))
die(“KwIndex: add_document: “.
“‘document_sub’ does not return enough documents”);
if (sizeof(&$doc_ids) > sizeof(&$docs))
die(“KwIndex: add_document: “.
“‘document_sub’ returns too many documents”);
# split documents into words
############################
while(list($id, $doc) = each($docs)) {
if (!isset($doc) || !strlen($doc)) continue;
$words = $this->_split_to_words($doc);
$num_of_words = sizeof(&$words);
# note: this means that numbers, etc are counted
$doclist[$id] = $num_of_words;
# filter non-qualifying words: 1-char length, numbers, words
# that are too long
$w2 = array();
while(list($k, $v) = each($words)) {
$len = strlen($v);
$lower_v = strtolower($v);
if ($len > 1 &&
$len < = $this->max_word_length &&
preg_match(“/[a-z]/”, $lower_v) &&
!isset($this->stoplist[$lower_v])) ++$w2[ $lower_v ];
}
while(list($k, $v) = each($w2)) {
$lower_k = strtolower($k);
if (!isset($wordlist[$lower_k]))
$wordlist[$lower_k] = array();
array_push($wordlist[$lower_k], array($id, $v/$num_of_words));
}
}
#_debug(“wordlist: “, Dumper($wordlist));
# submit to database
####################
$linkid = $this->linkid;
$idx = $this->index_name;
# lock the tables in case some other process remove a certain word
# between step 0 and 1 and 2 and 3
if(!mysql_query(“LOCK TABLES ${idx}_doclist WRITE, “.
“${idx}_vectorlist WRITE, “.
“${idx}_wordlist WRITE”,
$linkid)) {
$this->ERROR = “Can’t lock tables when adding documents: “.
mysql_error($linkid);
return;
}
# 0
# add the docs first
#_debug( “doclist = “, Dumper($doclist));
while(list($k,$v) = each($doclist)) {
if(!mysql_query(“REPLACE INTO ${idx}_doclist (id,n) VALUES (“.
“‘”.(addslashes($k)).”‘”.
“,”.
“‘”.(addslashes($v)).”‘”.
“)”,
$linkid)) {
$this->ERROR = “Can’t add doc id=`$_’ to doclist: “.
mysql_error($linkid);
mysql_query(“UNLOCK TABLES”, $linkid);
return;
}
}
# 1
# and then add the words
while(list($k,$v) = each($wordlist)) {
if(!mysql_query(“INSERT IGNORE INTO ${idx}_wordlist (word) “.
“VALUES (“.
“‘”.(addslashes($k)).”‘”.
“)”,
$linkid)) {
$this->ERROR = “Can’t add word `$k’ to wordlist: “.
mysql_error($linkid);
mysql_query(“UNLOCK TABLES”, $linkid);
return
;
}
}
# 2
# get the resulting word ids
$word_ids = array();
$e_wordlist = array();
reset($wordlist);
while(list($k,$v) = each($wordlist))
array_push($e_wordlist, “‘”.addslashes($k).”‘”);
if (sizeof(&$wordlist)) {
if(!($res = mysql_query(“SELECT id,word FROM ${idx}_wordlist “.
“WHERE word IN (“.
join(‘,’, $e_wordlist).
“)”,
$linkid))) {
$this->ERROR = “Can’t get data from wordlist: “.
mysql_error($linkid);
mysql_query(‘UNLOCK TABLES’, $linkid);
return;
}
while($row = mysql_fetch_row($res)) {
#echo “row = “, Dumper($row), ”
\n”;
$word_ids[ $row[1] ] = $row[0];
}
}
# 3
# now add the vectors
#_debug(“word_ids = “, Dumper($word_ids));
reset($wordlist);
while (list($word, $hitlist) = each($wordlist)) {
while(list($i, $hit) = each($hitlist)) {
#echo “adding word=$word, hit = ($hit[0], $hit[1])
\n”;
if(!mysql_query(“INSERT INTO ${idx}_vectorlist (wid,did,f)”.
“VALUES (“.
(“‘”.addslashes($word_ids[$word])).”‘,”.
(“‘”.addslashes($hit[0])).”‘,”.
(“‘”.addslashes($hit[1])).”‘)”,
$linkid)) {
$this->ERROR = “Can’t add to vectorlist: “.
mysql_error($linkid);
mysql_query(‘UNLOCK TABLES’, $linkid);
return;
}
}
}
# if all goes well, return TRUE
mysql_query(‘UNLOCK TABLES’, $linkid);
return 1;
}
function remove_document($doc_ids) {
if (!is_array(&$doc_ids))
die(“KwIndex: syntax: remove_document(array \$doc_ids)”);
if (!sizeof(&$doc_ids)) return 1;
$linkid = $this->linkid;
$idx = $this->index_name;
if(!mysql_query(“LOCK TABLES ${idx}_doclist WRITE, “.
“${idx}_vectorlist WRITE”,
$linkid)) {
$this->ERROR = “Can’t lock tables when removing documents: “.
mysql_error($linkid);
return;
}
if(!mysql_query(“DELETE FROM ${idx}_doclist WHERE id IN (“.
join(‘,’, $doc_ids).”)”,
$linkid)) {
$this->ERROR = “Can’t delete from doclist: “.
mysql_error($linkid);
mysql_query(‘UNLOCK TABLES’, $linkid);
return;
}
if(!mysql_query(“DELETE FROM ${idx}_vectorlist WHERE did IN (“.
join(‘,’, $doc_ids).”)”,
$linkid)) {
$this->ERROR = “Can’t delete from vectorlist: “.
mysql_error($linkid);
mysql_query(‘UNLOCK TABLES’, $linkid);
return;
}
# if all goes well, return TRUE
mysql_query(“UNLOCK TABLES”, $linkid);
return 1;
}
function update_document($doc_ids) {
if (!is_array(&$doc_ids))
die(“KwIndex: syntax: update_document(array \$doc_ids)”);
if (!sizeof(&$doc_ids)) return 1;
return $this->remove_document(&$doc_ids) &&
$this->add_document(&$doc_ids);
}
# find all words that are contained in at least $k % of all documents
function &common_word($k = 80) {
$linkid = $this->linkid;
$idx = $this->index_name;
# first select the number of documents
$num = $this->document_count();
if ($num == -1) {
$this->ERROR = “Can’t retrieve the number of documents: “.
mysql_error($linkid);
return;
}
# get the statistics from vectorlist
if(!($res1 = mysql_query(“SELECT wid,COUNT(*)/$num as k FROM
${idx}_vectorlist GROUP BY wid HAVING k>=”.
($k/100),
$linkid))) {
$this->ERROR = “Can’t retrieve common words: “.
mysql_error($linkid);
return;
}
$wids = array();
while($row = mysql_fetch_row($res1)) array_push($wids, $row[0]);
# convert it to word by consulting the wordlist table
$words = array();
if (sizeof(&$wids)) {
if (!($res2 = mysql_query(“SELECT word FROM ${idx}_wordlist “.
“WHERE id IN (“.join(‘,’, $wids).
“)”,
$linkid))) {
$this->ERROR = “Can’t retrieve common words: “.
mysql_error($linkid);
return;
}
while($row = mysql_fetch_row($res2))
array_push($words, $row[0]);
}
return $words;
}
# find all words that are not contained in all documents (vectorlist)
# XXX not yet written
function &orphan_word() {
return array();
}
# remove words from index
function remove_word($words) {
if (!is_array(&$words))
die(“KwIndex: syntax: remove_word(array \$words)”);
$linkid = $this->linkid;
$idx = $this->index_name;
if(!mysql_query(“LOCK TABLES ${idx}_wordlist WRITE, “.
“${idx}_vectorlist WRITE”,
$linkid)) {
$this->ERROR = “Can’t lock tables when removing words: “.
mysql_error($linkid);
return;
}
$e_words = array();
while(list($k,$v) = each($words))
array_push($e_words, “‘”.addslashes(strtolower($v)).”‘”);
# retrieve word ids
if(!($res0 = mysql_query(“SELECT id FROM ${idx}_wordlist WHERE “.
“word IN (“.join(‘,’, $e_words).”)”,
$linkid))) {
$this->ERROR = “Can’t delete from wordlist: “.
mysql_error($linkid);
mysql_query(‘UNLOCK TABLES’, $linkid);
return;
}
$word_ids = array();
while($row = mysql_fetch_row($res0))
array_push($word_ids, $row[0]);
$word_ids = join(‘,’, $word_ids); # we’ll make it a string
if (!strlen($word_ids)) return 1;
# delete from wordlist
if(!mysql_query(“DELETE FROM ${idx}_wordlist WHERE id IN “.
“($word_ids)”,
$linkid)) {
$this->ERROR = “Can’t delete from wordlist: “.
mysql_error($linkid);
mysql_query(“UNLOCK TABLES”, $linkid);
return;
}
if(!mysql_query(“DELETE FROM ${idx}_vectorlist WHERE wid IN “.
“($word_ids)”, $linkid)) {
$this->ERROR = “Can’t delete from vectorlist: “.
mysql_error($linkid);
mysql_query(“UNLOCK TABLES”, $linkid);
return;
}
return 1;
}
# add stop words. note: you must manually delete previously indexed
# words with delete_word()
function add_stop_word($words) {
if (!is_array(&$words))
die(“KwIndex: syntax: add_stop_word(array words)”);
if (!sizeof(&$words)) return 1;
$linkid = $this->linkid;
$idx = $this->index_name;
while(list($k, $v) = each($words)) {
$lv = strtolower($v);
if(!mysql_query(“REPLACE INTO ${idx}_stoplist (word) VALUES (“.
(“‘”.addslashes($lv).”‘”).
“)”, $linkid)) {
$this->ERROR = “Can’t add to stoplist: “.
mysql_error($linkid);
return;
}
$this->stoplist[ $lv ] = 1;
}
return 1;
}
# remove stop words from index
function remove_stop_word($words) {
if (!is_array(&$words))
die(“KwIndex: syntax: remove_stop_word(array words)”);
if (!sizeof(&$words)) return 1;
$linkid = $this->linkid;
$idx = $this->index_name;
$e_words = array();
while(list($k,$v) = each($words))
array_push($e_words, “‘”.addslashes(strtolower($v)).”‘”);
if(!mysql_query(“DELETE FROM ${idx}_stoplist WHERE word IN (“.
join(‘,’, $e_words).”)”,
$linkid)) {
$this->ERROR = “Can’t delete from stoplist: “.
mysql_error($linkid);
return;
}
while(list($k,$v) = each($words))
unset($this->stoplist[ strtolower($v) ]);
return 1;
}
function is_stop_word($word) {
return isset($this->stoplist[ strtolower($word) ]);
}
function &_search_or_match_count($is_count, &$args) {
if (!isset($args["words"]))
die(“KwIndex: search: option ‘words’ must be defined”);
$linkid = $this->linkid;
$idx = $this->index_name;
# split the words if we are offered a single string/not array
# (assume it’s a phrase)
$words = array();
if (is_array(&$args["words"])) {
$words = $args["words"];
} else {
$words = $this->_split_to_words($args["words"]);
}
# delete duplicate words, convert them all to lowercase
$hashwords = array();
while(list($k,$v) = each($words)) $hashwords[ strtolower($v) ] = 1;
$words = array_keys(&$hashwords);
if (!sizeof(&$words)) {
if ($is_count) {
return 0;
} else {
return array();
}
}
# first we retrieve the word ids
$op = $args["re"] ? ‘REGEXP’:'LIKE’;
$bool = isset($args['boolean']) && $args['boolean'] &&
strtoupper($args['boolean']) == ‘AND’ ? ‘AND’:'OR’;
$op_phrases = array();
while(list($k,$v) = each($words))
array_push($op_phrases, “word $op ‘”.addslashes($v).”‘”);
if (!($res0 = mysql_query(“SELECT id FROM ${idx}_wordlist WHERE “.
join(‘ OR ‘, $op_phrases),
$linkid))) {
$this->ERROR = “Can’t retrieve word ids: “.mysql_error($linkid);
return;
}
$word_ids = array();
while($row = mysql_fetch_row($res0)) array_push($word_ids, $row[0]);
if (!sizeof(&$word_ids) ||
($bool == ‘AND’ && sizeof(&$word_ids) < sizeof(&$words))) {
if ($is_count) {
return 0;
} else {
return array();
}
}
# and then we search the vectorlist
$can_optimize=0;
$stmt = ‘;
if ($is_count) {
if ($bool == ‘AND’ && !$args['re']) {
$stmt = ‘SELECT did,count(wid) as c ‘.
“FROM ${idx}_vectorlist WHERE wid IN (“.
join(‘,’,$word_ids).
“) “.
“GROUP BY did “.
“HAVING c >= “.sizeof(&$word_ids);
} else {
$can_optimize=1;
$stmt = “SELECT COUNT(DISTINCT did) “.
“FROM ${idx}_vectorlist WHERE wid IN (“.
join(‘,’,$word_ids).
“)”;
}
} else { // ! $is_count
$stmt = “SELECT did, count(wid) as c, avg(f) as a, “.
“count(wid)*count(wid)*count(wid)*avg(f) as ca “.
“FROM ${idx}_vectorlist WHERE wid IN (“.
join(‘,’,$word_ids).
“) “.
“GROUP BY did “.
($bool == ‘AND’ && !$args['re'] ?
“HAVING c >= “.sizeof(&$word_ids):’).
” ORDER BY ca DESC “.
(isset($args['num']) ? “LIMIT ” . (isset($args['start']) ?
(($args['start'] – 1).”,”.$args['num']) : $args['num'])
:’);
}
_debug(“search SQL: “, $stmt);
if(!($res = mysql_query($stmt, $linkid))) {
$this->ERROR = “Can’t search vectorlist: “.mysql_error($linkid);
return;
}
if ($is_count) {
if ($can_optimize) {
$row = mysql_fetch_row($res);
return $row[0];
} else {
return mysql_num_rows($res);
}
} else { // ! $is_count
$doc_ids = array();
while($row = mysql_fetch_row($res)) array_push($doc_ids, $row[0]);
return $doc_ids;
}
}
function &search($args) {
return $this->_search_or_match_count(0, &$args);
}
function &match_count($args) {
return $this->_search_or_match_count(1, &$args);
}
function remove_index() {
$linkid = $this->linkid;
$idx = $this->index_name;
if(!mysql_query(“DROP TABLE IF EXISTS ${idx}_wordlist”, $linkid)) {
$this->ERROR = “Can’t remove table ${idx}_wordlist: “.
mysql_error($linkid);
return;
}
if(!mysql_query(“DROP TABLE IF EXISTS ${idx}_doclist”, $linkid)) {
$this->ERROR = “Can’t remove table ${idx}_doclist: “.
mysql_error($linkid);
return;
}
if(!mysql_query(“DROP TABLE IF EXISTS ${idx}_vectorlist”, $linkid)) {
$this->ERROR = “Can’t remove table ${idx}_vectorlist: “.
mysql_error($linkid);
return;
}
if(!mysql_query(“DROP TABLE IF EXISTS ${idx}_stoplist”, $linkid)) {
$this->ERROR = “Can’t remove table ${idx}_stoplist: “.
mysql_error($linkid);
return;
}
return 1;
}
function empty_index() {
return $this->remove_index() && $this->_create_index();
}
# number of documents in the collection
function document_count() {
$linkid = $this->linkid;
$idx = $this->index_name;
if (!($res = mysql_query(“SELECT COUNT(*) FROM ${idx}_doclist”,
$linkid))) return;
$row = mysql_fetch_row($res);
return $row[0];
}
# number of unique words
function word_count() {
$linkid = $this->linkid;
$idx = $this->index_name;
if (!($res = mysql_query(“SELECT COUNT(*) FROM ${idx}_wordlist”,
$linkid))) return;
$row = mysql_fetch_row($res);
return $row[0];
}
# PRIVATE METHODS
#################
function &_split_to_words($str) {
preg_match_all(“/\b(\w[\w']*\w+|\w+)\b/”, $str, $matches);
return $matches[1];
}
>function _create_index() {
$linkid = $this->linkid;
$idx = $this->index_name;
$stmt = ‘;
# drop previous tables, if they exist
if (!$this->remove_index()) return;
# create doclist table
$stmt = “CREATE TABLE ${idx}_doclist ” .
‘(id ‘ . $this->_int_column_type($this->doclist_cardinality).
‘ AUTO_INCREMENT PRIMARY KEY, ‘ .
‘ n ‘ . $this->_int_column_type($this->wordlist_cardinality).
‘ NOT NULL’.
‘)’;
if (!mysql_query($stmt, $linkid))
die(“KwIndex: Can’t create table ${idx}_doclist: “.
mysql_error($linkid));
# create wordlist table
$stmt = “CREATE TABLE ${idx}_wordlist ” .
‘(id ‘ . $this->_int_column_type($this->wordlist_cardinality) .
‘ AUTO_INCREMENT PRIMARY KEY, ‘ .
” word VARCHAR($this->max_word_length)” .
‘ BINARY NOT NULL, ‘ .
“UNIQUE (word) ” .
‘)’;
if(!mysql_query($stmt, $linkid))
die(“KwIndex: Can’t create table ${idx}_wordlist: “.
mysql_error($linkid));
# create stoplist table
$stmt = “CREATE TABLE ${idx}_stoplist ” .
‘(id ‘ . $this->_int_column_type($this->wordlist_cardinality).
‘ AUTO_INCREMENT PRIMARY KEY, ‘ .
” word VARCHAR($this->max_word_length)” .
‘ BINARY NOT NULL, ‘ .
“UNIQUE (word) ” .
‘)’;
if (!mysql_query($stmt, $linkid))
die(“KwIndex: Can’t create table ${idx}_stoplist: “.
mysql_error($linkid));
# create vectorlist table
$stmt = “CREATE TABLE ${idx}_vectorlist ” .
‘(wid ‘. $this->_int_column_type($this->wordlist_cardinality).
‘ NOT NULL, ‘ .
‘did ‘. $this->_int_column_type($this->doclist_cardinality).
‘ NOT NULL, ‘.
‘UNIQUE (wid,did), ‘.
‘f FLOAT(10,4) NOT NULL’.
‘)’;
if (!mysql_query($stmt, $linkid)) {
die(“KwIndex: Can’t create table ${idx}_stoplist: “.
mysql_error($linkid));
}
$this->stoplist = array();
return 1;
}
function _int_column_type($cardinality) {
if ($cardinality >= 16*1024*1024) return ‘INT UNSIGNED’;
if ($cardinality >= 64*1024) return ‘MEDIUMINT UNSIGNED’;
if ($cardinality >= 256) return ‘SMALLINT UNSIGNED’;
return ‘TINYINT UNSIGNED’;
}
function &_index_tables() {
$idx = $this->index_name;
$tables = array(
“${idx}_doclist”,
“${idx}_wordlist”,
“${idx}_vectorlist”,
“${idx}_stoplist”);
return $tables;
}
function _index_exists() {
$linkid = $this->linkid;
$idx = $this->index_name;
if (!($res = mysql_list_tables($this->db_name, $linkid)))
die(“Can’t list table: “.mysql_error($linkid));
$existing_tables = array();
$i = 0;
while ($i < mysql_num_rows($res)) {
$existing_tables[ mysql_tablename($res, $i) ] = 1;
$i++;
}
$index_tables = $this->_index_tables();
while(list($k,$v) = each($index_tables)) {
if (!isset($existing_tables[$v])) return 0;
}
return 1;
}
} // class
?>
