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move logic that creates the SQL query into LogQueryBuilder class
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@mattab
mattab committed Dec 5, 2014
1 parent 764a8c1 commit 5c14cf8
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261 changes: 261 additions & 0 deletions core/DataAccess/LogQueryBuilder.php
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<?php
/**
* Piwik - free/libre analytics platform
*
* @link http://piwik.org
* @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
*
*/

namespace Piwik\DataAccess;


use Exception;
use Piwik\Common;
use Piwik\Segment\SegmentExpression;

class LogQueryBuilder
{


/**
* @param $segmentExpression
* @param $select
* @param $from
* @param $where
* @param $bind
* @param $orderBy
* @param $groupBy
* @return array
* @throws Exception
*/
public function getSelectQueryString(SegmentExpression $segmentExpression, $select, $from, $where, $bind, $orderBy, $groupBy)
{
if (!is_array($from)) {
$from = array($from);
}

if (!$segmentExpression->isEmpty()) {
$segmentExpression->parseSubExpressionsIntoSqlExpressions($from);

$joins = $this->generateJoins($from);
$from = $joins['sql'];
$joinWithSubSelect = $joins['joinWithSubSelect'];

$segmentSql = $segmentExpression->getSql();
$segmentWhere = $segmentSql['where'];
if (!empty($segmentWhere)) {
if (!empty($where)) {
$where = "( $where )
AND
($segmentWhere)";
} else {
$where = $segmentWhere;
}
}

$bind = array_merge($bind, $segmentSql['bind']);
} else {
$joins = $this->generateJoins($from);
$from = $joins['sql'];
$joinWithSubSelect = $joins['joinWithSubSelect'];
}

if ($joinWithSubSelect) {
$sql = $this->buildWrappedSelectQuery($select, $from, $where, $orderBy, $groupBy);
} else {
$sql = $this->buildSelectQuery($select, $from, $where, $orderBy, $groupBy);
}
return array(
'sql' => $sql,
'bind' => $bind
);
}
/**
* Generate the join sql based on the needed tables
* @param array $tables tables to join
* @throws Exception if tables can't be joined
* @return array
*/
private function generateJoins($tables)
{
$knownTables = array("log_visit", "log_link_visit_action", "log_conversion", "log_conversion_item");
$visitsAvailable = $actionsAvailable = $conversionsAvailable = $conversionItemAvailable = false;
$joinWithSubSelect = false;
$sql = '';

// make sure the tables are joined in the right order
// base table first, then action before conversion
// this way, conversions can be joined on idlink_va
$actionIndex = array_search("log_link_visit_action", $tables);
$conversionIndex = array_search("log_conversion", $tables);
if ($actionIndex > 0 && $conversionIndex > 0 && $actionIndex > $conversionIndex) {
$tables[$actionIndex] = "log_conversion";
$tables[$conversionIndex] = "log_link_visit_action";
}

// same as above: action before visit
$actionIndex = array_search("log_link_visit_action", $tables);
$visitIndex = array_search("log_visit", $tables);
if ($actionIndex > 0 && $visitIndex > 0 && $actionIndex > $visitIndex) {
$tables[$actionIndex] = "log_visit";
$tables[$visitIndex] = "log_link_visit_action";
}

foreach ($tables as $i => $table) {
if (is_array($table)) {
// join condition provided
$alias = isset($table['tableAlias']) ? $table['tableAlias'] : $table['table'];
$sql .= "
LEFT JOIN " . Common::prefixTable($table['table']) . " AS " . $alias
. " ON " . $table['joinOn'];
continue;
}

if (!in_array($table, $knownTables)) {
throw new Exception("Table '$table' can't be used for segmentation");
}

$tableSql = Common::prefixTable($table) . " AS $table";

if ($i == 0) {
// first table
$sql .= $tableSql;
} else {
if ($actionsAvailable && $table == "log_conversion") {
// have actions, need conversions => join on idlink_va
$join = "log_conversion.idlink_va = log_link_visit_action.idlink_va "
. "AND log_conversion.idsite = log_link_visit_action.idsite";
} else if ($actionsAvailable && $table == "log_visit") {
// have actions, need visits => join on idvisit
$join = "log_visit.idvisit = log_link_visit_action.idvisit";
} else if ($visitsAvailable && $table == "log_link_visit_action") {
// have visits, need actions => we have to use a more complex join
// we don't hande this here, we just return joinWithSubSelect=true in this case
$joinWithSubSelect = true;
$join = "log_link_visit_action.idvisit = log_visit.idvisit";
} else if ($conversionsAvailable && $table == "log_link_visit_action") {
// have conversions, need actions => join on idlink_va
$join = "log_conversion.idlink_va = log_link_visit_action.idlink_va";
} else if (($visitsAvailable && $table == "log_conversion")
|| ($conversionsAvailable && $table == "log_visit")
) {
// have visits, need conversion (or vice versa) => join on idvisit
// notice that joining conversions on visits has lower priority than joining it on actions
$join = "log_conversion.idvisit = log_visit.idvisit";

// if conversions are joined on visits, we need a complex join
if ($table == "log_conversion") {
$joinWithSubSelect = true;
}
} elseif ($conversionItemAvailable && $table === 'log_visit') {
$join = "log_conversion_item.idvisit = log_visit.idvisit";
} elseif ($conversionItemAvailable && $table === 'log_link_visit_action') {
$join = "log_conversion_item.idvisit = log_link_visit_action.idvisit";
} elseif ($conversionItemAvailable && $table === 'log_conversion') {
$join = "log_conversion_item.idvisit = log_conversion.idvisit";
} else {
throw new Exception("Table '$table' can't be joined for segmentation");
}

// the join sql the default way
$sql .= "
LEFT JOIN $tableSql ON $join";
}

// remember which tables are available
$visitsAvailable = ($visitsAvailable || $table == "log_visit");
$actionsAvailable = ($actionsAvailable || $table == "log_link_visit_action");
$conversionsAvailable = ($conversionsAvailable || $table == "log_conversion");
$conversionItemAvailable = ($conversionItemAvailable || $table == "log_conversion_item");
}

$return = array(
'sql' => $sql,
'joinWithSubSelect' => $joinWithSubSelect
);
return $return;

}

/**
* Build select query the normal way
* @param string $select fieldlist to be selected
* @param string $from tablelist to select from
* @param string $where where clause
* @param string $orderBy order by clause
* @param string $groupBy group by clause
* @return string
*/
private function buildSelectQuery($select, $from, $where, $orderBy, $groupBy)
{
$sql = "
SELECT
$select
FROM
$from";

if ($where) {
$sql .= "
WHERE
$where";
}

if ($groupBy) {
$sql .= "
GROUP BY
$groupBy";
}

if ($orderBy) {
$sql .= "
ORDER BY
$orderBy";
}

return $sql;
}

/**
* Build a select query where actions have to be joined on visits (or conversions)
* In this case, the query gets wrapped in another query so that grouping by visit is possible
* @param string $select
* @param string $from
* @param string $where
* @param string $orderBy
* @param string $groupBy
* @throws Exception
* @return string
*/
private function buildWrappedSelectQuery($select, $from, $where, $orderBy, $groupBy)
{
$matchTables = "(log_visit|log_conversion_item|log_conversion|log_action)";
preg_match_all("/". $matchTables ."\.[a-z0-9_\*]+/", $select, $matches);
$neededFields = array_unique($matches[0]);

if (count($neededFields) == 0) {
throw new Exception("No needed fields found in select expression. "
. "Please use a table prefix.");
}

$select = preg_replace('/'.$matchTables.'\./', 'log_inner.', $select);
$orderBy = preg_replace('/'.$matchTables.'\./', 'log_inner.', $orderBy);
$groupBy = preg_replace('/'.$matchTables.'\./', 'log_inner.', $groupBy);

$from = "(
SELECT
" . implode(",
", $neededFields) . "
FROM
$from
WHERE
$where
GROUP BY log_visit.idvisit
) AS log_inner";

$where = false;
$query = $this->buildSelectQuery($select, $from, $where, $orderBy, $groupBy);
return $query;
}

}
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