<?
 
/*****************************************************************************
 Class Query v.1.1
******************************************************************************
 
 Author: edward@planet-three.co.uk
 
 Purpose:
 
        To add a logical query to the SearchEngine class. The logic can be 
        one of the following : AND , OR, NOT.
 
 Usage:     
        aquery = new Query("NOT", array("apple", "pear", "bannana"));
 
*****************************************************************************/
 
class Query {
 
//PRIVATE:
 
    var $m_words;
    var $m_logic;
 
//PUBLIC
 
    //
    // Constructor  
 
    // logic: <AND | OR | NOT>
    // words: words to be searched for given logic
 
    function Query($logic, $words) {
 
        $this->m_words = $words;
        $this->m_logic = $logic;
    }   
 
    // print attributes of query
 
    function p() {
 
        echo "$this->m_logic";
        reset($this->m_words);
        while(list($i, $word) = each($this->m_words))
            echo ":$word";
    }
};
 
/*****************************************************************************
 Class QueryGenerator v.1.2
******************************************************************************
 
 Author: edward@planet-three.co.uk
 
 purpose: 
 
        Generates selection query strings
 usage:     
        query1 = new Query("AND", array("rabbit", "horse", "cow"));
        query2 = new Query("OR",  array("dogs", "cats", "kangaroos"));
        query3 = new Query("NOT", array("sheep"));
 
        querygen = new QueryGenerator(array(query1, query2, query3));
        query = 
           querygen->GetQueryString("animal_table", "mamals_field", "ID_field");
 
        resultid = mysql_query(query);      
        while(row = mysql_fetch_row(resultid))
            echo "got row id ",row["ID_field"],"<br>";
 
*******************************************************************************/
 
class QueryGenerator {
 
    var $m_Querys;
    var $m_start;
    var $m_offset;  
 
    var $m_wordmatch;
    var $m_casematch;
 
//PUBLIC:
 
    //  querys   : array of Query objects
    //  wordmatch: only match whole words
 
    function QueryGenerator($Querys, $wordmatch=false, $casematch=false) {
 
        $this->m_Querys = $Querys;
        $this->m_wordmatch = $wordmatch;
        $this->m_casematch = $casematch;
 
        $this->Restrict(0,0);
    }
 
    // start  : start searching data at this pos
    // offset : number of records to search after pos
 
    function Restrict($start, $offset) {
 
        $this->m_start  = $start;
        $this->m_offset = $offset;  
    }
 
    function GetRestrict(&$start, &$offset) {
 
        $start = $this->m_start;
        $offset = $this->m_offset;
    }
 
    // table : database table name
    // searchfield: field(s) to search in for resultfield(s)
    // resultfield: field(s) retrieved from search match
    // NOTE: field must be separated by "," eg, "field1,field2"
 
    // RETURN: function returns resultfield
 
    function GetQueryString($table, $searchfield, $resultfield="ID") {
 
        // begin query string
        $query_string = "SELECT $resultfield FROM $table WHERE ";
 
        // get the query string     
        $query_string .= $this->BuildQueryString($table, $searchfield);
 
        // append limit     
        if ($this->m_start || $this->m_offset) {
            $query_string .= "LIMIT $this->m_start";    
            if($this->m_offset)          
                $query_string .= ",$this->m_offset";
        }
 
        return $query_string;
    }   
 
    // build Query string that will return the number of rows selected
 
    function GetCountQueryString($table, $searchfield) {
 
        // begin query string
        $query_string = "SELECT count(*) FROM $table WHERE ";
 
        // get the query string     
        $query_string .= $this->BuildQueryString($table, $searchfield);
 
        return $query_string;
    }       
 
//PRIVATE:
 
 
    // main function that generates the entire query
    function BuildQueryString($table, $searchfield) {
 
        // parse searchfields
        $searchfields = explode(",", $searchfield);     
        if(!is_array($searchfields)) 
            $searchfields=array($searchfield);
 
        // build query for each searchfield
        while ($searchfield = current($searchfields)) {
 
            // uppercase do case insensitive man
            if (!$this->m_casematch)
                $searchfield = "UPPER(".$searchfield.")";
 
            $firstquery = true;
            $query_string .= "(";
 
            // build current query
            reset($this->m_Querys);                         
            while($query = current($this->m_Querys)) {                          
 
                // append logic         
                if ($firstquery)
                    $firstquery=false;
                else if ($query->m_logic == "NOT")
                    $query_string.="AND";
                else
                    $query_string.=$query->m_logic;                                 
 
                // append where clause
                $query_string .= 
                $this->BuildWhereClause($searchfield, $query);                                              
                next($this->m_Querys);
            }
            $query_string .=")";                                
            if (next($searchfields))
                $query_string .= "OR";  
        }                                   
        return $query_string;
    }
 
    // build where clause
    function BuildWhereClause($searchfield, $query) {
 
        $query_string.="(";                                     
        while($word = current($query->m_words)) {               
 
            if (!$this->m_casematch)
                $word = strtoupper($word);          
 
            if ($this->m_wordmatch)
                $search_type = "REGEXP '[[:<:]]".$word."[[:>:]]'";
            else
                $search_type = "REGEXP '$word'";
 
            if ($query->m_logic == "NOT") 
                $query_string.="$searchfield NOT ";
            else
                $query_string.="$searchfield ";
 
            $query_string.= $search_type;                   
            if (next($query->m_words))              
                $query_string.=" OR ";
        }                                                               
        $query_string.=")";                                                     
        return $query_string;
    }   
};
 
?>