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Commit 5b736070 by Scott
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Move selectspec processing to separate class

parent d8d6fb0d
Showing with 11 additions and 300 deletions
qa-include/db/selects.php
......@@ -31,45 +31,15 @@ require_once QA_INCLUDE_DIR.'db/maxima.php';
* Return the results of all the SELECT operations specified by the supplied selectspec parameters, while also
* performing all pending selects that have not yet been executed. If only one parameter is supplied, return its
* result, otherwise return an array of results indexed as per the parameters.
* @deprecated 1.9.0 Use DbSelect->selectWithPending() instead.
* @return mixed
*/
function qa_db_select_with_pending() // any number of parameters read via func_get_args()
{
require_once QA_INCLUDE_DIR . 'app/options.php';
global $qa_db_pending_selectspecs, $qa_db_pending_results;
$selectspecs = func_get_args();
$singleresult = (count($selectspecs) == 1);
$outresults = array();
foreach ($selectspecs as $key => $selectspec) { // can pass null parameters
if (empty($selectspec)) {
unset($selectspecs[$key]);
$outresults[$key] = null;
}
}
if (is_array($qa_db_pending_selectspecs)) {
foreach ($qa_db_pending_selectspecs as $pendingid => $selectspec) {
if (!isset($qa_db_pending_results[$pendingid])) {
$selectspecs['pending_' . $pendingid] = $selectspec;
}
}
}
$outresults = $outresults + qa_db_multi_select($selectspecs);
if (is_array($qa_db_pending_selectspecs)) {
foreach ($qa_db_pending_selectspecs as $pendingid => $selectspec) {
if (!isset($qa_db_pending_results[$pendingid])) {
$qa_db_pending_results[$pendingid] = $outresults['pending_' . $pendingid];
unset($outresults['pending_' . $pendingid]);
}
}
}
$dbSelect = new \Q2A\Database\DbSelect(qa_service('database'));
return $singleresult ? $outresults[0] : $outresults;
return qa_call([$dbSelect, 'selectWithPending'], $selectspecs);
}
......
qa-include/qa-db.php
......@@ -429,26 +429,30 @@ function qa_db_list_tables($onlyTablesWithPrefix = false)
/**
* Return the data specified by a single $selectspec - see long comment above.
* @deprecated 1.9.0 Use DbConnection->singleSelect() instead.
* @deprecated 1.9.0 Use DbSelect->singleSelect() instead.
* @param array $selectspec
* @return mixed
*/
function qa_db_single_select($selectspec)
{
return qa_service('database')->singleSelect($selectspec);
$dbSelect = new \Q2A\Database\DbSelect(qa_service('database'));
return $dbSelect->singleSelect($selectspec);
}
/**
* Return the data specified by each element of $selectspecs, where the keys of the
* returned array match the keys of the supplied $selectspecs array. See long comment above.
* @deprecated 1.9.0 Use DbConnection->multiSelect() instead.
* @deprecated 1.9.0 Use DbSelect->multiSelect() instead.
* @param array $selectspecs
* @return array
*/
function qa_db_multi_select($selectspecs)
{
return qa_service('database')->multiSelect($selectspecs);
$dbSelect = new \Q2A\Database\DbSelect(qa_service('database'));
return $dbSelect->multiSelect($selectspecs);
}
......
qa-src/Database/DbConnection.php
......@@ -22,7 +22,6 @@ use PDO;
use PDOException;
use PDOStatement;
use Q2A\Database\Exceptions\SelectSpecException;
use Q2A\Storage\CacheFactory;
/**
* Core database class. Handles all SQL queries within Q2A.
......@@ -248,268 +247,6 @@ class DbConnection
return $stmt;
}
/*
The selectspec array can contain the elements below. See db/selects.php for lots of examples.
By default, singleSelect() and multiSelect() return the data for each selectspec as a numbered
array of arrays, one per row. The array for each row has column names in the keys, and data in the values.
But this can be changed using the 'arraykey', 'arrayvalue' and 'single' in the selectspec.
Note that even if you specify ORDER BY in 'source', the final results may not be ordered. This is because
the SELECT could be done within a UNION that (annoyingly) doesn't maintain order. Use 'sortasc' or 'sortdesc'
to fix this. You can however rely on the combination of ORDER BY and LIMIT retrieving the appropriate records.
'columns' => Array of names of columns to be retrieved (required)
If a value in the columns array has an integer key, it is retrieved AS itself (in a SQL sense).
If a value in the columns array has a non-integer key, it is retrieved AS that key.
Values in the columns array can include table specifiers before the period.
'source' => Any SQL after FROM, including table names, JOINs, GROUP BY, ORDER BY, WHERE, etc... (required)
'arguments' => Substitutions in order for $s and #s in the query, applied in qa_db_apply_sub() above (required)
'arraykey' => Name of column to use for keys of the outer-level returned array, instead of numbers by default
'arrayvalue' => Name of column to use for values of outer-level returned array, instead of arrays by default
'single' => If true, return the array for a single row and don't embed it within an outer-level array
'sortasc' => Sort the output ascending by this column
'sortdesc' => Sort the output descending by this column
Why does multiSelect() combine usually unrelated SELECT statements into a single query?
Because if the database and web servers are on different computers, there will be latency.
This way we ensure that every read pageview on the site requires as few DB queries as possible, so
that we pay for this latency only one time.
For writes we worry less, since the user is more likely to be expecting a delay.
If QA_OPTIMIZE_DISTANT_DB is set to false in qa-config.php, we assume zero latency and go back to
simple queries, since this will allow both MySQL and PHP to provide quicker results.
*/
/**
* Return the data specified by a single $selectspec - see long comment above.
* @param $selectspec
* @return array|mixed
*/
public function singleSelect($selectspec)
{
// check for cached results
if (isset($selectspec['caching'])) {
$cacheDriver = CacheFactory::getCacheDriver();
$cacheKey = 'query:' . $selectspec['caching']['key'];
if ($cacheDriver->isEnabled()) {
$queryData = $cacheDriver->get($cacheKey);
if ($queryData !== null) {
return $queryData;
}
}
}
$query = 'SELECT ';
foreach ($selectspec['columns'] as $columnas => $columnfrom) {
$query .= is_int($columnas) ? "$columnfrom, " : "$columnfrom AS `$columnas`, ";
}
$query = substr($query, 0, -2);
if (isset($selectspec['source']) && strlen($selectspec['source']) > 0) {
$query .= ' FROM ' . $selectspec['source'];
}
$params = isset($selectspec['arguments']) ? $selectspec['arguments'] : array();
$arraykey = isset($selectspec['arraykey']) ? $selectspec['arraykey'] : null;
$result = $this->query($query, $params);
$data = $result->fetchAllAssoc($arraykey); // arrayvalue is applied in formatSelect()
$this->formatSelect($data, $selectspec); // post-processing
// save cached results
if (isset($selectspec['caching'])) {
if ($cacheDriver->isEnabled()) {
$cacheDriver->set($cacheKey, $data, $selectspec['caching']['ttl']);
}
}
return $data;
}
/**
* Return the data specified by each element of $selectspecs, where the keys of the
* returned array match the keys of the supplied $selectspecs array. See long comment above.
* @param array $selectspecs
* @return array
*/
public function multiSelect($selectspecs)
{
// Perform simple queries if the database is local or there are only 0-1 selectspecs
if (!QA_OPTIMIZE_DISTANT_DB || count($selectspecs) <= 1) {
$outresults = array();
foreach ($selectspecs as $selectkey => $selectspec) {
$outresults[$selectkey] = $this->singleSelect($selectspec);
}
return $outresults;
}
// Otherwise, parse columns for each spec to deal with columns without an 'AS' specification
foreach ($selectspecs as $selectkey => $selectspec) {
$selectspecs[$selectkey]['outcolumns'] = array();
$selectspecs[$selectkey]['autocolumn'] = array();
foreach ($selectspec['columns'] as $columnas => $columnfrom) {
if (is_int($columnas)) {
// fetch column name if not already provided in the array key
$periodpos = strpos($columnfrom, '.');
$columnas = is_numeric($periodpos) ? substr($columnfrom, $periodpos + 1) : $columnfrom;
$selectspecs[$selectkey]['autocolumn'][$columnas] = true;
}
if (isset($selectspecs[$selectkey]['outcolumns'][$columnas])) {
qa_fatal_error('Duplicate column name in DbConnection::multiSelect()');
}
$selectspecs[$selectkey]['outcolumns'][$columnas] = $columnfrom;
}
if (isset($selectspec['arraykey']) && !isset($selectspecs[$selectkey]['outcolumns'][$selectspec['arraykey']])) {
qa_fatal_error('Used arraykey not in columns in DbConnection::multiSelect()');
}
if (isset($selectspec['arrayvalue']) && !isset($selectspecs[$selectkey]['outcolumns'][$selectspec['arrayvalue']])) {
qa_fatal_error('Used arrayvalue not in columns in DbConnection::multiSelect()');
}
}
// Work out the full list of columns used
$outcolumns = array();
foreach ($selectspecs as $selectspec) {
$outcolumns = array_unique(array_merge($outcolumns, array_keys($selectspec['outcolumns'])));
}
// Build the query based on this full list
$query = '';
$queryParams = array();
foreach ($selectspecs as $selectkey => $selectspec) {
$subquery = "(SELECT " . $this->pdo->quote($selectkey) . ' AS selectkey';
foreach ($outcolumns as $columnas) {
$subquery .= ', ' . (isset($selectspec['outcolumns'][$columnas]) ? $selectspec['outcolumns'][$columnas] : 'NULL');
if (empty($query) && !isset($selectspec['autocolumn'][$columnas])) {
$subquery .= ' AS ' . $columnas;
}
}
if (isset($selectspec['source']) && strlen($selectspec['source']) > 0) {
$subquery .= ' FROM ' . $selectspec['source'];
}
$subquery .= ')';
if (strlen($query)) {
$query .= ' UNION ALL ';
}
$query .= $subquery;
if (isset($selectspec['arguments'])) {
$queryParams = array_merge($queryParams, array_values($selectspec['arguments']));
}
}
// Perform query and extract results
$stmt = $this->query($query, $queryParams);
$rawresults = $stmt->fetchAllAssoc();
$outresults = array();
foreach ($selectspecs as $selectkey => $selectspec) {
$outresults[$selectkey] = array();
}
foreach ($rawresults as $rawresult) {
$selectkey = $rawresult['selectkey'];
$selectspec = $selectspecs[$selectkey];
$keepresult = array();
foreach ($selectspec['outcolumns'] as $columnas => $columnfrom) {
$keepresult[$columnas] = $rawresult[$columnas];
}
if (isset($selectspec['arraykey'])) {
$outresults[$selectkey][$keepresult[$selectspec['arraykey']]] = $keepresult;
} else {
$outresults[$selectkey][] = $keepresult;
}
}
// Post-processing to apply various stuff include sorting request, since we can't rely on ORDER BY due to UNION
foreach ($selectspecs as $selectkey => $selectspec) {
$this->formatSelect($outresults[$selectkey], $selectspec);
}
return $outresults;
}
/**
* Post-process $outresult according to $selectspec, applying 'sortasc', 'sortdesc', 'arrayvalue' and 'single'.
* @param array $outresult
* @param array $selectspec
*/
private function formatSelect(&$outresult, $selectspec)
{
// PHP's sorting algorithm is not 'stable', so we use '_order_' element to keep stability.
// By contrast, MySQL's ORDER BY does seem to give the results in a reliable order.
if (isset($selectspec['sortasc'])) {
require_once QA_INCLUDE_DIR . 'util/sort.php';
$index = 0;
foreach ($outresult as $key => $value) {
$outresult[$key]['_order_'] = $index++;
}
qa_sort_by($outresult, $selectspec['sortasc'], '_order_');
} elseif (isset($selectspec['sortdesc'])) {
require_once QA_INCLUDE_DIR . 'util/sort.php';
if (isset($selectspec['sortdesc_2'])) {
qa_sort_by($outresult, $selectspec['sortdesc'], $selectspec['sortdesc_2']);
} else {
$index = count($outresult);
foreach ($outresult as $key => $value) {
$outresult[$key]['_order_'] = $index--;
}
qa_sort_by($outresult, $selectspec['sortdesc'], '_order_');
}
$outresult = array_reverse($outresult, true);
}
if (isset($selectspec['arrayvalue'])) {
foreach ($outresult as $key => $value) {
$outresult[$key] = $value[$selectspec['arrayvalue']];
}
}
if (@$selectspec['single']) {
$outresult = count($outresult) ? reset($outresult) : null;
}
}
/**
* Return the value of the auto-increment column for the last inserted row.
* @return string
......
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