dbi = $dbi; $this->relation = $relation; $this->transformations = $transformations; $this->template = $template; } /** * build the html for columns of $colTypeCategory category * in form of given $listType in a table * * @param string $db current database * @param string $table current table * @param string $colTypeCategory supported all|Numeric|String|Spatial * |Date and time using the _pgettext() format * @param string $listType type of list to build, supported dropdown|checkbox * * @return string HTML for list of columns in form of given list types */ public function getHtmlForColumnsList( $db, $table, $colTypeCategory = 'all', $listType = 'dropdown' ) { $columnTypeList = []; if ($colTypeCategory !== 'all') { $types = $this->dbi->types->getColumns(); $columnTypeList = $types[$colTypeCategory]; if (! is_array($columnTypeList)) { $columnTypeList = []; } } $this->dbi->selectDb($db); $columns = $this->dbi->getColumns($db, $table, true); $type = ''; $selectColHtml = ''; foreach ($columns as $column => $def) { if (isset($def['Type'])) { $extractedColumnSpec = Util::extractColumnSpec($def['Type']); $type = $extractedColumnSpec['type']; } if (! empty($columnTypeList) && ! in_array(mb_strtoupper($type), $columnTypeList)) { continue; } if ($listType === 'checkbox') { $selectColHtml .= '' . htmlspecialchars($column) . ' [ ' . htmlspecialchars($def['Type']) . ' ]
'; } else { $selectColHtml .= ''; } } return $selectColHtml; } /** * get the html of the form to add the new column to given table * * @param int $numFields number of columns to add * @param string $db current database * @param string $table current table * @param array $columnMeta array containing default values for the fields * * @return string HTML */ public function getHtmlForCreateNewColumn( $numFields, $db, $table, array $columnMeta = [] ) { $relationParameters = $this->relation->getRelationParameters(); $contentCells = []; $availableMime = []; $mimeMap = []; if ($relationParameters->browserTransformationFeature !== null && $GLOBALS['cfg']['BrowseMIME']) { $mimeMap = $this->transformations->getMime($db, $table); $availableMime = $this->transformations->getAvailableMimeTypes(); } $commentsMap = $this->relation->getComments($db, $table); for ($columnNumber = 0; $columnNumber < $numFields; $columnNumber++) { $contentCells[$columnNumber] = [ 'column_number' => $columnNumber, 'column_meta' => $columnMeta, 'type_upper' => '', 'length_values_input_size' => 8, 'length' => '', 'extracted_columnspec' => [], 'submit_attribute' => null, 'comments_map' => $commentsMap, 'fields_meta' => null, 'is_backup' => true, 'move_columns' => [], 'available_mime' => $availableMime, 'mime_map' => $mimeMap, ]; } $charsets = Charsets::getCharsets($this->dbi, $GLOBALS['cfg']['Server']['DisableIS']); $collations = Charsets::getCollations($this->dbi, $GLOBALS['cfg']['Server']['DisableIS']); $charsetsList = []; foreach ($charsets as $charset) { $collationsList = []; foreach ($collations[$charset->getName()] as $collation) { $collationsList[] = [ 'name' => $collation->getName(), 'description' => $collation->getDescription(), ]; } $charsetsList[] = [ 'name' => $charset->getName(), 'description' => $charset->getDescription(), 'collations' => $collationsList, ]; } return $this->template->render('columns_definitions/table_fields_definitions', [ 'is_backup' => true, 'fields_meta' => null, 'relation_parameters' => $relationParameters, 'content_cells' => $contentCells, 'change_column' => $_POST['change_column'] ?? $_GET['change_column'] ?? null, 'is_virtual_columns_supported' => Compatibility::isVirtualColumnsSupported($this->dbi->getVersion()), 'browse_mime' => $GLOBALS['cfg']['BrowseMIME'], 'supports_stored_keyword' => Compatibility::supportsStoredKeywordForVirtualColumns( $this->dbi->getVersion() ), 'server_version' => $this->dbi->getVersion(), 'max_rows' => intval($GLOBALS['cfg']['MaxRows']), 'char_editing' => $GLOBALS['cfg']['CharEditing'], 'attribute_types' => $this->dbi->types->getAttributes(), 'privs_available' => $GLOBALS['col_priv'] && $GLOBALS['is_reload_priv'], 'max_length' => $this->dbi->getVersion() >= 50503 ? 1024 : 255, 'charsets' => $charsetsList, ]); } /** * build the html for step 1.1 of normalization * * @param string $db current database * @param string $table current table * @param string $normalizedTo up to which step normalization will go, * possible values 1nf|2nf|3nf * * @return string HTML for step 1.1 */ public function getHtmlFor1NFStep1($db, $table, $normalizedTo) { $step = 1; $stepTxt = __('Make all columns atomic'); $html = "

" . __('First step of normalization (1NF)') . '

'; $html .= "
" . '
' . '' . __('Step 1.') . $step . ' ' . $stepTxt . '' . '

' . __( 'Do you have any column which can be split into more than' . ' one column? ' . 'For example: address can be split into street, city, country and zip.' ) . "
( " . __('Show me the central list of columns that are not already in this table') . ' )

' . "

" . __( 'Select a column which can be split into more ' . 'than one (on select of \'no such column\', it\'ll move to next step).' ) . '

' . "
" . "' . '' . __('split into ') . "" . '
' . "
" . '
' . '
' . '
'; return $html; } /** * build the html contents of various html elements in step 1.2 * * @param string $db current database * @param string $table current table * * @return string[] HTML contents for step 1.2 */ public function getHtmlContentsFor1NFStep2($db, $table) { $step = 2; $stepTxt = __('Have a primary key'); $primary = Index::getPrimary($table, $db); $hasPrimaryKey = '0'; $legendText = __('Step 1.') . $step . ' ' . $stepTxt; $extra = ''; if ($primary !== false) { $headText = __('Primary key already exists.'); $subText = __('Taking you to next step…'); $hasPrimaryKey = '1'; } else { $headText = __( 'There is no primary key; please add one.
' . 'Hint: A primary key is a column ' . '(or combination of columns) that uniquely identify all rows.' ); $subText = '' . Generator::getIcon( 'b_index_add', __( 'Add a primary key on existing column(s)' ) ) . ''; $extra = __('If it\'s not possible to make existing column combinations as primary key') . '
' . '' . __('+ Add a new primary key column') . ''; } return [ 'legendText' => $legendText, 'headText' => $headText, 'subText' => $subText, 'hasPrimaryKey' => $hasPrimaryKey, 'extra' => $extra, ]; } /** * build the html contents of various html elements in step 1.4 * * @param string $db current database * @param string $table current table * * @return string[] HTML contents for step 1.4 */ public function getHtmlContentsFor1NFStep4($db, $table) { $step = 4; $stepTxt = __('Remove redundant columns'); $legendText = __('Step 1.') . $step . ' ' . $stepTxt; $headText = __( 'Do you have a group of columns which on combining gives an existing' . ' column? For example, if you have first_name, last_name and' . ' full_name then combining first_name and last_name gives full_name' . ' which is redundant.' ); $subText = __( 'Check the columns which are redundant and click on remove. ' . "If no redundant column, click on 'No redundant column'" ); $extra = $this->getHtmlForColumnsList($db, $table, 'all', 'checkbox') . '
' . '' . ''; return [ 'legendText' => $legendText, 'headText' => $headText, 'subText' => $subText, 'extra' => $extra, ]; } /** * build the html contents of various html elements in step 1.3 * * @param string $db current database * @param string $table current table * * @return string[] HTML contents for step 1.3 */ public function getHtmlContentsFor1NFStep3($db, $table) { $step = 3; $stepTxt = __('Move repeating groups'); $legendText = __('Step 1.') . $step . ' ' . $stepTxt; $headText = __( 'Do you have a group of two or more columns that are closely ' . 'related and are all repeating the same attribute? For example, ' . 'a table that holds data on books might have columns such as book_id, ' . 'author1, author2, author3 and so on which form a ' . 'repeating group. In this case a new table (book_id, author) should ' . 'be created.' ); $subText = __( 'Check the columns which form a repeating group. If no such group, click on \'No repeating group\'' ); $extra = $this->getHtmlForColumnsList($db, $table, 'all', 'checkbox') . '
' . '' . ''; $primary = Index::getPrimary($table, $db); $primarycols = $primary === false ? [] : $primary->getColumns(); $pk = []; foreach ($primarycols as $col) { $pk[] = $col->getName(); } return [ 'legendText' => $legendText, 'headText' => $headText, 'subText' => $subText, 'extra' => $extra, 'primary_key' => json_encode($pk), ]; } /** * build html contents for 2NF step 2.1 * * @param string $db current database * @param string $table current table * * @return string[] HTML contents for 2NF step 2.1 */ public function getHtmlFor2NFstep1($db, $table) { $legendText = __('Step 2.') . '1 ' . __('Find partial dependencies'); $primary = Index::getPrimary($table, $db); $primarycols = $primary === false ? [] : $primary->getColumns(); $pk = []; $subText = ''; $selectPkForm = ''; $extra = ''; foreach ($primarycols as $col) { $pk[] = $col->getName(); $selectPkForm .= '' . htmlspecialchars($col->getName()); } $key = implode(', ', $pk); if (count($primarycols) > 1) { $this->dbi->selectDb($db); $columns = $this->dbi->getColumnNames($db, $table); if (count($pk) == count($columns)) { $headText = sprintf( __( 'No partial dependencies possible as ' . 'no non-primary column exists since primary key ( %1$s ) ' . 'is composed of all the columns in the table.' ), htmlspecialchars($key) ) . '
'; $extra = '

' . __('Table is already in second normal form.') . '

'; } else { $headText = sprintf( __( 'The primary key ( %1$s ) consists of more than one column ' . 'so we need to find the partial dependencies.' ), htmlspecialchars($key) ) . '
' . __('Please answer the following question(s) carefully to obtain a correct normalization.') . '
' . __( '+ Show me the possible partial dependencies based on data in the table' ) . ''; $subText = __( 'For each column below, ' . 'please select the minimal set of columns among given set ' . 'whose values combined together are sufficient' . ' to determine the value of the column.' ); $cnt = 0; foreach ($columns as $column) { if (in_array($column, $pk)) { continue; } $cnt++; $extra .= '' . sprintf( __('\'%1$s\' depends on:'), htmlspecialchars($column) ) . '
'; $extra .= '
' . $selectPkForm . '


'; } } } else { $headText = sprintf( __( 'No partial dependencies possible as the primary key ( %1$s ) has just one column.' ), htmlspecialchars($key) ) . '
'; $extra = '

' . __('Table is already in second normal form.') . '

'; } return [ 'legendText' => $legendText, 'headText' => $headText, 'subText' => $subText, 'extra' => $extra, 'primary_key' => $key, ]; } /** * build the html for showing the tables to have in order to put current table in 2NF * * @param array $partialDependencies array containing all the dependencies * @param string $table current table * * @return string HTML */ public function getHtmlForNewTables2NF(array $partialDependencies, $table) { $html = '

' . sprintf( __( 'In order to put the ' . 'original table \'%1$s\' into Second normal form we need ' . 'to create the following tables:' ), htmlspecialchars($table) ) . '

'; $tableName = $table; $i = 1; foreach ($partialDependencies as $key => $dependents) { $html .= '

' . '( ' . htmlspecialchars($key) . '' . (count($dependents) > 0 ? ', ' : '') . htmlspecialchars(implode(', ', $dependents)) . ' )'; $i++; $tableName = 'table' . $i; } return $html; } /** * create/alter the tables needed for 2NF * * @param array $partialDependencies array containing all the partial dependencies * @param object $tablesName name of new tables * @param string $table current table * @param string $db current database * * @return array */ public function createNewTablesFor2NF(array $partialDependencies, $tablesName, $table, $db) { $dropCols = false; $nonPKCols = []; $queries = []; $error = false; $headText = '

' . sprintf( __('The second step of normalization is complete for table \'%1$s\'.'), htmlspecialchars($table) ) . '

'; if (count((array) $partialDependencies) === 1) { return [ 'legendText' => __('End of step'), 'headText' => $headText, 'queryError' => $error, ]; } $message = ''; $this->dbi->selectDb($db); foreach ($partialDependencies as $key => $dependents) { if ($tablesName->$key != $table) { $keys = explode(', ', $key); $quotedKeys = []; foreach ($keys as $eachKey) { $quotedKeys[] = Util::backquote($eachKey); } $backquotedKey = implode(', ', $quotedKeys); $quotedDependents = []; foreach ($dependents as $dependent) { $quotedDependents[] = Util::backquote($dependent); } $queries[] = 'CREATE TABLE ' . Util::backquote($tablesName->$key) . ' SELECT DISTINCT ' . $backquotedKey . (count($dependents) > 0 ? ', ' : '') . implode(',', $quotedDependents) . ' FROM ' . Util::backquote($table) . ';'; $queries[] = 'ALTER TABLE ' . Util::backquote($tablesName->$key) . ' ADD PRIMARY KEY(' . $backquotedKey . ');'; $nonPKCols = array_merge($nonPKCols, $dependents); } else { $dropCols = true; } } if ($dropCols) { $query = 'ALTER TABLE ' . Util::backquote($table); foreach ($nonPKCols as $col) { $query .= ' DROP ' . Util::backquote($col) . ','; } $query = trim($query, ', '); $query .= ';'; $queries[] = $query; } else { $queries[] = 'DROP TABLE ' . Util::backquote($table); } foreach ($queries as $query) { if (! $this->dbi->tryQuery($query)) { $message = Message::error(__('Error in processing!')); $message->addMessage( Message::rawError($this->dbi->getError()), '

' ); $error = true; break; } } return [ 'legendText' => __('End of step'), 'headText' => $headText, 'queryError' => $error, 'extra' => $message, ]; } /** * build the html for showing the new tables to have in order * to put given tables in 3NF * * @param object $dependencies containing all the dependencies * @param array $tables tables formed after 2NF and need to convert to 3NF * @param string $db current database * * @return array containing html and the list of new tables */ public function getHtmlForNewTables3NF($dependencies, array $tables, $db) { $html = ''; $i = 1; $newTables = []; foreach ($tables as $table => $arrDependson) { if (count(array_unique($arrDependson)) === 1) { continue; } $primary = Index::getPrimary($table, $db); $primarycols = $primary === false ? [] : $primary->getColumns(); $pk = []; foreach ($primarycols as $col) { $pk[] = $col->getName(); } $html .= '

' . sprintf( __( 'In order to put the ' . 'original table \'%1$s\' into Third normal form we need ' . 'to create the following tables:' ), htmlspecialchars($table) ) . '

'; $tableName = $table; $columnList = []; foreach ($arrDependson as $key) { $dependents = $dependencies->$key; if ($key == $table) { $key = implode(', ', $pk); } $tmpTableCols = array_merge(explode(', ', $key), $dependents); sort($tmpTableCols); if (in_array($tmpTableCols, $columnList)) { continue; } $columnList[] = $tmpTableCols; $html .= '

' . '( ' . htmlspecialchars($key) . '' . (count($dependents) > 0 ? ', ' : '') . htmlspecialchars(implode(', ', $dependents)) . ' )'; $newTables[$table][$tableName] = [ 'pk' => $key, 'nonpk' => implode(', ', $dependents), ]; $i++; $tableName = 'table' . $i; } } return [ 'html' => $html, 'newTables' => $newTables, 'success' => true, ]; } /** * create new tables or alter existing to get 3NF * * @param array $newTables list of new tables to be created * @param string $db current database * * @return array */ public function createNewTablesFor3NF(array $newTables, $db) { $queries = []; $dropCols = false; $error = false; $headText = '

' . __('The third step of normalization is complete.') . '

'; if (count($newTables) === 0) { return [ 'legendText' => __('End of step'), 'headText' => $headText, 'queryError' => $error, ]; } $message = ''; $this->dbi->selectDb($db); foreach ($newTables as $originalTable => $tablesList) { foreach ($tablesList as $table => $cols) { if ($table != $originalTable) { $pkArray = explode(', ', $cols['pk']); $quotedPkArray = []; foreach ($pkArray as $pk) { $quotedPkArray[] = Util::backquote($pk); } $quotedPk = implode(', ', $quotedPkArray); $nonpkArray = explode(', ', $cols['nonpk']); $quotedNonpkArray = []; foreach ($nonpkArray as $nonpk) { $quotedNonpkArray[] = Util::backquote($nonpk); } $quotedNonpk = implode(', ', $quotedNonpkArray); $queries[] = 'CREATE TABLE ' . Util::backquote($table) . ' SELECT DISTINCT ' . $quotedPk . ', ' . $quotedNonpk . ' FROM ' . Util::backquote($originalTable) . ';'; $queries[] = 'ALTER TABLE ' . Util::backquote($table) . ' ADD PRIMARY KEY(' . $quotedPk . ');'; } else { $dropCols = $cols; } } if ($dropCols) { $columns = $this->dbi->getColumnNames($db, $originalTable); $colPresent = array_merge( explode(', ', $dropCols['pk']), explode(', ', $dropCols['nonpk']) ); $query = 'ALTER TABLE ' . Util::backquote($originalTable); foreach ($columns as $col) { if (in_array($col, $colPresent)) { continue; } $query .= ' DROP ' . Util::backquote($col) . ','; } $query = trim($query, ', '); $query .= ';'; $queries[] = $query; } else { $queries[] = 'DROP TABLE ' . Util::backquote($originalTable); } $dropCols = false; } foreach ($queries as $query) { if (! $this->dbi->tryQuery($query)) { $message = Message::error(__('Error in processing!')); $message->addMessage( Message::rawError($this->dbi->getError()), '

' ); $error = true; break; } } return [ 'legendText' => __('End of step'), 'headText' => $headText, 'queryError' => $error, 'extra' => $message, ]; } /** * move the repeating group of columns to a new table * * @param string $repeatingColumns comma separated list of repeating group columns * @param string $primaryColumns comma separated list of column in primary key * of $table * @param string $newTable name of the new table to be created * @param string $newColumn name of the new column in the new table * @param string $table current table * @param string $db current database * * @return array */ public function moveRepeatingGroup( $repeatingColumns, $primaryColumns, $newTable, $newColumn, $table, $db ) { $repeatingColumnsArr = explode(', ', $repeatingColumns); $primaryColumnsArray = explode(',', $primaryColumns); $columns = []; foreach ($primaryColumnsArray as $column) { $columns[] = Util::backquote($column); } $primaryColumns = implode(',', $columns); $query1 = 'CREATE TABLE ' . Util::backquote($newTable); $query2 = 'ALTER TABLE ' . Util::backquote($table); $message = Message::success( sprintf( __('Selected repeating group has been moved to the table \'%s\''), htmlspecialchars($table) ) ); $first = true; $error = false; foreach ($repeatingColumnsArr as $repeatingColumn) { if (! $first) { $query1 .= ' UNION '; } $first = false; $quotedRepeatingColumn = Util::backquote($repeatingColumn); $query1 .= ' SELECT ' . $primaryColumns . ',' . $quotedRepeatingColumn . ' as ' . Util::backquote($newColumn) . ' FROM ' . Util::backquote($table); $query2 .= ' DROP ' . $quotedRepeatingColumn . ','; } $query2 = trim($query2, ','); $queries = [ $query1, $query2, ]; $this->dbi->selectDb($db); foreach ($queries as $query) { if (! $this->dbi->tryQuery($query)) { $message = Message::error(__('Error in processing!')); $message->addMessage( Message::rawError($this->dbi->getError()), '

' ); $error = true; break; } } return [ 'queryError' => $error, 'message' => $message, ]; } /** * build html for 3NF step 1 to find the transitive dependencies * * @param string $db current database * @param array $tables tables formed after 2NF and need to process for 3NF * * @return string[] */ public function getHtmlFor3NFstep1($db, array $tables) { $legendText = __('Step 3.') . '1 ' . __('Find transitive dependencies'); $extra = ''; $headText = __('Please answer the following question(s) carefully to obtain a correct normalization.'); $subText = __( 'For each column below, ' . 'please select the minimal set of columns among given set ' . 'whose values combined together are sufficient' . ' to determine the value of the column.
' . 'Note: A column may have no transitive dependency, ' . 'in that case you don\'t have to select any.' ); $cnt = 0; foreach ($tables as $table) { $primary = Index::getPrimary($table, $db); $primarycols = $primary === false ? [] : $primary->getColumns(); $selectTdForm = ''; $pk = []; foreach ($primarycols as $col) { $pk[] = $col->getName(); } $this->dbi->selectDb($db); $columns = $this->dbi->getColumnNames($db, $table); if (count($columns) - count($pk) <= 1) { continue; } foreach ($columns as $column) { if (in_array($column, $pk)) { continue; } $selectTdForm .= '' . '' . htmlspecialchars($column) . ''; } foreach ($columns as $column) { if (in_array($column, $pk)) { continue; } $cnt++; $extra .= '' . sprintf( __('\'%1$s\' depends on:'), htmlspecialchars($column) ) . '
'; $extra .= '
' . $selectTdForm . '


'; } } if ($extra == '') { $headText = __( 'No Transitive dependencies possible as the table doesn\'t have any non primary key columns' ); $subText = ''; $extra = '

' . __('Table is already in Third normal form!') . '

'; } return [ 'legendText' => $legendText, 'headText' => $headText, 'subText' => $subText, 'extra' => $extra, ]; } /** * get html for options to normalize table * * @return string HTML */ public function getHtmlForNormalizeTable() { $htmlOutput = '
' . Url::getHiddenInputs($GLOBALS['db'], $GLOBALS['table']) . ''; $htmlOutput .= '
'; $htmlOutput .= '' . __('Improve table structure (Normalization):') . ''; $htmlOutput .= '

' . __('Select up to what step you want to normalize') . '

'; $htmlOutput .= '
'; $htmlOutput .= '
'; $htmlOutput .= '
'; $htmlOutput .= '
'; $htmlOutput .= '
'; $htmlOutput .= '
'; $htmlOutput .= '
' . "" . __( 'Hint: Please follow the procedure carefully in order to obtain correct normalization' ) . '' . '' . '
' . '
' . ''; return $htmlOutput; } /** * find all the possible partial dependencies based on data in the table. * * @param string $table current table * @param string $db current database * * @return string HTML containing the list of all the possible partial dependencies */ public function findPartialDependencies($table, $db) { $dependencyList = []; $this->dbi->selectDb($db); $columnNames = $this->dbi->getColumnNames($db, $table); $columns = []; foreach ($columnNames as $column) { $columns[] = Util::backquote($column); } $totalRowsRes = $this->dbi->fetchResult( 'SELECT COUNT(*) FROM (SELECT * FROM ' . Util::backquote($table) . ' LIMIT 500) as dt;' ); $totalRows = $totalRowsRes[0]; $primary = Index::getPrimary($table, $db); $primarycols = $primary === false ? [] : $primary->getColumns(); $pk = []; foreach ($primarycols as $col) { $pk[] = Util::backquote($col->getName()); } $partialKeys = $this->getAllCombinationPartialKeys($pk); $distinctValCount = $this->findDistinctValuesCount( array_unique( array_merge($columns, $partialKeys) ), $table ); foreach ($columns as $column) { if (in_array($column, $pk)) { continue; } foreach ($partialKeys as $partialKey) { if ( ! $partialKey || ! $this->checkPartialDependency( $partialKey, $column, $table, $distinctValCount[$partialKey], $distinctValCount[$column], $totalRows ) ) { continue; } $dependencyList[$partialKey][] = $column; } } $html = __('This list is based on a subset of the table\'s data and is not necessarily accurate. ') . '
'; foreach ($dependencyList as $dependon => $colList) { $html .= '' . '' . '' . htmlspecialchars(str_replace('`', '', (string) $dependon)) . ' -> ' . '' . htmlspecialchars(str_replace('`', '', implode(', ', $colList))) . '' . ''; } if (empty($dependencyList)) { $html .= '

' . __('No partial dependencies found!') . '

'; } $html .= '
'; return $html; } /** * check whether a particular column is dependent on given subset of primary key * * @param string $partialKey the partial key, subset of primary key, * each column in key supposed to be backquoted * @param string $column backquoted column on whose dependency being checked * @param string $table current table * @param int $pkCnt distinct value count for given partial key * @param int $colCnt distinct value count for given column * @param int $totalRows total distinct rows count of the table */ private function checkPartialDependency( $partialKey, $column, $table, $pkCnt, $colCnt, $totalRows ): bool { $query = 'SELECT ' . 'COUNT(DISTINCT ' . $partialKey . ',' . $column . ') as pkColCnt ' . 'FROM (SELECT * FROM ' . Util::backquote($table) . ' LIMIT 500) as dt;'; $res = $this->dbi->fetchResult($query, null, null); $pkColCnt = $res[0]; if ($pkCnt && $pkCnt == $colCnt && $colCnt == $pkColCnt) { return true; } return $totalRows && $totalRows == $pkCnt; } /** * function to get distinct values count of all the column in the array $columns * * @param array $columns array of backquoted columns whose distinct values * need to be counted. * @param string $table table to which these columns belong * * @return array associative array containing the count */ private function findDistinctValuesCount(array $columns, $table) { $result = []; $query = 'SELECT '; foreach ($columns as $column) { if (! $column) { continue; } //each column is already backquoted $query .= 'COUNT(DISTINCT ' . $column . ') as \'' . $column . '_cnt\', '; } $query = trim($query, ', '); $query .= ' FROM (SELECT * FROM ' . Util::backquote($table) . ' LIMIT 500) as dt;'; $res = $this->dbi->fetchResult($query, null, null); foreach ($columns as $column) { if (! $column) { continue; } $result[$column] = $res[0][$column . '_cnt'] ?? null; } return $result; } /** * find all the possible partial keys * * @param array $primaryKey array containing all the column present in primary key * * @return array containing all the possible partial keys(subset of primary key) */ private function getAllCombinationPartialKeys(array $primaryKey) { $results = ['']; foreach ($primaryKey as $element) { foreach ($results as $combination) { $results[] = trim($element . ',' . $combination, ','); } } array_pop($results); //remove key which consist of all primary key columns return $results; } }