I have created a search functionality to my cake application. It is built from multiple select boxes in which you can select data, then it cycles through the selected options and implements them to the SQL syntax.
Basically this is how the function looks like:
$selectedFilters = $this->data;
$selectSQL = 'SELECT
agencies.agency, agencies.website_url, agencies.status, agencies.size, agencies.id, OfficeData.id, ContactData.name, ContactData.surname, ContactData.job_title, ContactData.email,
ContactData.mobile, OfficeCountryData.country
FROM agencies
LEFT JOIN (SELECT agencies_industries.agency_id, agencies_industries.industry_id FROM agencies_industries) AS IndustryData ON agencies.id = IndustryData.agency_id
LEFT JOIN (SELECT agencies_professions.agency_id, agencies_professions.profession_id FROM agencies_professions) AS ProfessionData ON agencies.id = ProfessionData.agency_id
LEFT JOIN (SELECT agencies_sectors.agency_id, agencies_sectors.sector_id FROM agencies_sectors) AS SectorData ON agencies.id = SectorData.agency_id
LEFT JOIN (SELECT agencies_seniorities.agency_id, agencies_seniorities.seniority_id FROM agencies_seniorities) AS SeniorityData ON agencies.id = SeniorityData.agency_id
LEFT JOIN (SELECT agencies_zones.agency_id, agencies_zones.zone_id FROM agencies_zones) AS ZonesData ON agencies.id = ZonesData.agency_id
LEFT JOIN (SELECT agencies_countries.agency_id, agencies_countries.country_id FROM agencies_countries) AS CountryData ON agencies.id = CountryData.agency_id
LEFT JOIN (SELECT agencies_regions.agency_id, agencies_regions.region_id FROM agencies_regions) AS RegionData ON agencies.id = RegionData.agency_id
LEFT JOIN (SELECT agencies_cities.agency_id, agencies_cities.city_id FROM agencies_cities) AS CityData ON agencies.id = CityData.agency_id
LEFT JOIN (SELECT agencies_specialisms.agency_id, agencies_specialisms.specialism_id FROM agencies_specialisms) AS SpecialismData ON agencies.id = SpecialismData.agency_id
LEFT JOIN (SELECT offices.id, offices.agency_id, offices.hq FROM offices WHERE offices.hq = "1") AS OfficeData ON agencies.id = OfficeData.agency_id
LEFT JOIN (SELECT countries.id, countries.country FROM countries) AS OfficeCountryData ON OfficeData.hq = OfficeCountryData.id
LEFT JOIN (SELECT contacts.name, contacts.surname, contacts.agency_id, contacts.job_title, contacts.email, contacts.mobile FROM contacts) AS ContactData ON agencies.id = ContactData.agency_id
';
$whereSQL = ' WHERE 1 = 1 ';
foreach($selectedFilters as $key)
foreach($key as $name=>$value){
if(is_array($key))
foreach($key as $key=>$value){
$i = 0;
$connector = 'AND';
if(is_array($value)){
foreach($value as $value){
if($i > 0)
$connector = 'OR';
$i++;
switch($key){
case 'Profession': $whereSQL .= $connector.' ProfessionData.profession_id = ' . $value . ' ';
break;
case 'Specialism': $whereSQL .= $connector.' SpecialismData.specialism_id = ' . $value . ' ';
break;
case 'SubSpecialism': $whereSQL .= ''; //$whereSQL .= $connector.' SubData.sub_specialism_id = ' . $value . ' ';
break;
case 'Seniority': $whereSQL .= $connector.' SeniorityData.seniority_id = ' . $value . ' ';
break;
case 'Industry': $whereSQL .= $connector.' IndustryData.industry_id = ' . $value . ' ';
break;
case 'Zone': $whereSQL .= $connector.' ZonesData.zone_id = ' . $value . ' ';
break;
case 'Country': $whereSQL .= $connector.' CountryData.country_id = ' . $value . ' ';
break;
case 'Region': $whereSQL .= $connector.' RegionData.region_id = ' . $value . ' ';
break;
case 'City': $whereSQL .= $connector.' CityData.city_id = ' . $value . ' ';
break;
case 'Sector': $whereSQL .= $connector.' SectorData.sector_id = ' . $value . ' ';
break;
case 'status': $whereSQL .= $connector.' agencies.status = "' . $value . '" ';
break;
case 'size': $whereSQL .= $connector.' agencies.size = "' . $value . '" ';
break;
}
}
}
else
if(!isBlank($value) && $key != 'Search')
$whereSQL .= $connector.' agencies.'.$key.' = "'.$value.'" ';
}
}
$groupBySQL = 'GROUP BY agencies.id ORDER BY agencies.id ASC';
$resultAgencies = $this->Agency->query($selectSQL . $whereSQL . $groupBySQL);
$this->set(compact('resultAgencies'));
The problem I encountered with my search is that it works really slow. This happens because of using too many LEFT JOIN commands. Every LEFT JOIN selects data from distinct tables and gathers them all creating another table. Then the data is displayed.
I need someone to give me a hint how to do this not using so many LEFT JOINs.
Cheers.
Try this one:
But even then it might be slow since you join too many tables. But it’s hard to tell without knowing anything about your data and the amount of rows that you’ll return. You might want to move some JOINS to a subquery (like country) if you only return a few rows. Or you can add that information in a seperate query.
Edit:
Without knowing your data and db-structure it’s hard to tell. There are a lot of things that influence the speed of your query. First rewrite your query so that tables that are not used for your selection (i.e. the WHERE) or fields you want to show are not used in your query. So if you make no selection (emtpy $selectedFilters) the you don’t have to include the industries, professions, sectors, seniorities, etc tables.:
Second take a good look at your indexes for each table. Make sure you have an index on the fields you use in the JOINS.
Third, look at the field types you use. Don’t use a INT if a SMALLINT is large enough.
Finaly: Normalization is great, but sometimes it’s better to combine some things, even if that means you have duplicate data.