/libraries/classes/Plugins/Export/ExportSql.php

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<?php
/**
 * Set of functions used to build SQL dumps of tables
 */

declare(strict_types=1);

namespace PhpMyAdmin\Plugins\Export;

use PhpMyAdmin\Charsets;
use PhpMyAdmin\DatabaseInterface;
use PhpMyAdmin\FieldMetadata;
use PhpMyAdmin\Plugins\ExportPlugin;
use PhpMyAdmin\Properties\Options\Groups\OptionsPropertyMainGroup;
use PhpMyAdmin\Properties\Options\Groups\OptionsPropertyRootGroup;
use PhpMyAdmin\Properties\Options\Groups\OptionsPropertySubgroup;
use PhpMyAdmin\Properties\Options\Items\BoolPropertyItem;
use PhpMyAdmin\Properties\Options\Items\MessageOnlyPropertyItem;
use PhpMyAdmin\Properties\Options\Items\NumberPropertyItem;
use PhpMyAdmin\Properties\Options\Items\RadioPropertyItem;
use PhpMyAdmin\Properties\Options\Items\SelectPropertyItem;
use PhpMyAdmin\Properties\Options\Items\TextPropertyItem;
use PhpMyAdmin\Properties\Plugins\ExportPluginProperties;
use PhpMyAdmin\SqlParser\Components\CreateDefinition;
use PhpMyAdmin\SqlParser\Context;
use PhpMyAdmin\SqlParser\Parser;
use PhpMyAdmin\SqlParser\Statements\CreateStatement;
use PhpMyAdmin\SqlParser\Token;
use PhpMyAdmin\Util;
use PhpMyAdmin\Version;

use function __;
use function bin2hex;
use function count;
use function defined;
use function explode;
use function implode;
use function in_array;
use function intval;
use function is_array;
use function mb_strlen;
use function mb_strpos;
use function mb_substr;
use function preg_quote;
use function preg_replace;
use function preg_split;
use function sprintf;
use function str_repeat;
use function str_replace;
use function strtotime;
use function strtoupper;
use function trigger_error;

use const E_USER_ERROR;
use const PHP_VERSION;

/**
 * Handles the export for the SQL class
 */
class ExportSql extends ExportPlugin
{
    /**
     * Whether charset header was sent.
     *
     * @var bool
     */
    private $sentCharset = false;

    protected function init(): void
    {
        // Avoids undefined variables, use NULL so isset() returns false
        if (isset($GLOBALS['sql_backquotes'])) {
            return;
        }

        $GLOBALS['sql_backquotes'] = null;
    }

    /**
     * @psalm-return non-empty-lowercase-string
     */
    public function getName(): string
    {
        return 'sql';
    }

    protected function setProperties(): ExportPluginProperties
    {
        global $plugin_param, $dbi;

        $hideSql = false;
        $hideStructure = false;
        if ($plugin_param['export_type'] === 'table' && ! $plugin_param['single_table']) {
            $hideStructure = true;
            $hideSql = true;
        }

        // In case we have `raw_query` parameter set,
        // we initialize SQL option
        if (isset($_REQUEST['raw_query'])) {
            $hideStructure = false;
            $hideSql = false;
        }

        $exportPluginProperties = new ExportPluginProperties();
        $exportPluginProperties->setText('SQL');
        $exportPluginProperties->setExtension('sql');
        $exportPluginProperties->setMimeType('text/x-sql');

        if ($hideSql) {
            return $exportPluginProperties;
        }

        $exportPluginProperties->setOptionsText(__('Options'));

        // create the root group that will be the options field for
        // $exportPluginProperties
        // this will be shown as "Format specific options"
        $exportSpecificOptions = new OptionsPropertyRootGroup('Format Specific Options');

        // general options main group
        $generalOptions = new OptionsPropertyMainGroup('general_opts');

        // comments
        $subgroup = new OptionsPropertySubgroup('include_comments');
        $leaf = new BoolPropertyItem(
            'include_comments',
            __(
                'Display comments <i>(includes info such as export timestamp, PHP version, and server version)</i>'
            )
        );
        $subgroup->setSubgroupHeader($leaf);

        $leaf = new TextPropertyItem(
            'header_comment',
            __('Additional custom header comment (\n splits lines):')
        );
        $subgroup->addProperty($leaf);
        $leaf = new BoolPropertyItem(
            'dates',
            __(
                'Include a timestamp of when databases were created, last updated, and last checked'
            )
        );
        $subgroup->addProperty($leaf);
        if (! empty($GLOBALS['cfgRelation']['relation'])) {
            $leaf = new BoolPropertyItem(
                'relation',
                __('Display foreign key relationships')
            );
            $subgroup->addProperty($leaf);
        }

        if (! empty($GLOBALS['cfgRelation']['mimework'])) {
            $leaf = new BoolPropertyItem(
                'mime',
                __('Display media types')
            );
            $subgroup->addProperty($leaf);
        }

        $generalOptions->addProperty($subgroup);

        // enclose in a transaction
        $leaf = new BoolPropertyItem(
            'use_transaction',
            __('Enclose export in a transaction')
        );
        $leaf->setDoc(
            [
                'programs',
                'mysqldump',
                'option_mysqldump_single-transaction',
            ]
        );
        $generalOptions->addProperty($leaf);

        // disable foreign key checks
        $leaf = new BoolPropertyItem(
            'disable_fk',
            __('Disable foreign key checks')
        );
        $leaf->setDoc(
            [
                'manual_MySQL_Database_Administration',
                'server-system-variables',
                'sysvar_foreign_key_checks',
            ]
        );
        $generalOptions->addProperty($leaf);

        // export views as tables
        $leaf = new BoolPropertyItem(
            'views_as_tables',
            __('Export views as tables')
        );
        $generalOptions->addProperty($leaf);

        // export metadata
        $leaf = new BoolPropertyItem(
            'metadata',
            __('Export metadata')
        );
        $generalOptions->addProperty($leaf);

        // compatibility maximization
        $compats = $dbi->getCompatibilities();
        if (count($compats) > 0) {
            $values = [];
            foreach ($compats as $val) {
                $values[$val] = $val;
            }

            $leaf = new SelectPropertyItem(
                'compatibility',
                __(
                    'Database system or older MySQL server to maximize output compatibility with:'
                )
            );
            $leaf->setValues($values);
            $leaf->setDoc(
                [
                    'manual_MySQL_Database_Administration',
                    'Server_SQL_mode',
                ]
            );
            $generalOptions->addProperty($leaf);

            unset($values);
        }

        // what to dump (structure/data/both)
        $subgroup = new OptionsPropertySubgroup(
            'dump_table',
            __('Dump table')
        );
        $leaf = new RadioPropertyItem('structure_or_data');
        $leaf->setValues(
            [
                'structure' => __('structure'),
                'data' => __('data'),
                'structure_and_data' => __('structure and data'),
            ]
        );
        $subgroup->setSubgroupHeader($leaf);
        $generalOptions->addProperty($subgroup);

        // add the main group to the root group
        $exportSpecificOptions->addProperty($generalOptions);

        // structure options main group
        if (! $hideStructure) {
            $structureOptions = new OptionsPropertyMainGroup(
                'structure',
                __('Object creation options')
            );
            $structureOptions->setForce('data');

            // begin SQL Statements
            $subgroup = new OptionsPropertySubgroup();
            $leaf = new MessageOnlyPropertyItem(
                'add_statements',
                __('Add statements:')
            );
            $subgroup->setSubgroupHeader($leaf);

            // server export options
            if ($plugin_param['export_type'] === 'server') {
                $leaf = new BoolPropertyItem(
                    'drop_database',
                    sprintf(__('Add %s statement'), '<code>DROP DATABASE IF EXISTS</code>')
                );
                $subgroup->addProperty($leaf);
            }

            if ($plugin_param['export_type'] === 'database') {
                $createClause = '<code>CREATE DATABASE / USE</code>';
                $leaf = new BoolPropertyItem(
                    'create_database',
                    sprintf(__('Add %s statement'), $createClause)
                );
                $subgroup->addProperty($leaf);
            }

            if ($plugin_param['export_type'] === 'table') {
                $dropClause = $dbi->getTable($GLOBALS['db'], $GLOBALS['table'])->isView()
                    ? '<code>DROP VIEW</code>'
                    : '<code>DROP TABLE</code>';
            } else {
                $dropClause = '<code>DROP TABLE / VIEW / PROCEDURE / FUNCTION / EVENT</code>';
            }

            $dropClause .= '<code> / TRIGGER</code>';

            $leaf = new BoolPropertyItem(
                'drop_table',
                sprintf(__('Add %s statement'), $dropClause)
            );
            $subgroup->addProperty($leaf);

            $subgroupCreateTable = new OptionsPropertySubgroup();

            // Add table structure option
            $leaf = new BoolPropertyItem(
                'create_table',
                sprintf(__('Add %s statement'), '<code>CREATE TABLE</code>')
            );
            $subgroupCreateTable->setSubgroupHeader($leaf);

            $leaf = new BoolPropertyItem(
                'if_not_exists',
                '<code>IF NOT EXISTS</code> ' . __(
                    '(less efficient as indexes will be generated during table creation)'
                )
            );
            $subgroupCreateTable->addProperty($leaf);

            $leaf = new BoolPropertyItem(
                'auto_increment',
                sprintf(__('%s value'), '<code>AUTO_INCREMENT</code>')
            );
            $subgroupCreateTable->addProperty($leaf);

            $subgroup->addProperty($subgroupCreateTable);

            // Add view option
            $subgroupCreateView = new OptionsPropertySubgroup();
            $leaf = new BoolPropertyItem(
                'create_view',
                sprintf(__('Add %s statement'), '<code>CREATE VIEW</code>')
            );
            $subgroupCreateView->setSubgroupHeader($leaf);

            $leaf = new BoolPropertyItem(
                'simple_view_export',
                /* l10n: Allow simplifying exported view syntax to only "CREATE VIEW" */
                __('Use simple view export')
            );
            $subgroupCreateView->addProperty($leaf);

            $leaf = new BoolPropertyItem(
                'view_current_user',
                __('Exclude definition of current user')
            );
            $subgroupCreateView->addProperty($leaf);

            $leaf = new BoolPropertyItem(
                'or_replace_view',
                sprintf(__('%s view'), '<code>OR REPLACE</code>')
            );
            $subgroupCreateView->addProperty($leaf);

            $subgroup->addProperty($subgroupCreateView);

            $leaf = new BoolPropertyItem(
                'procedure_function',
                sprintf(
                    __('Add %s statement'),
                    '<code>CREATE PROCEDURE / FUNCTION / EVENT</code>'
                )
            );
            $subgroup->addProperty($leaf);

            // Add triggers option
            $leaf = new BoolPropertyItem(
                'create_trigger',
                sprintf(__('Add %s statement'), '<code>CREATE TRIGGER</code>')
            );
            $subgroup->addProperty($leaf);

            $structureOptions->addProperty($subgroup);

            $leaf = new BoolPropertyItem(
                'backquotes',
                __(
                    'Enclose table and column names with backquotes '
                    . '<i>(Protects column and table names formed with'
                    . ' special characters or keywords)</i>'
                )
            );

            $structureOptions->addProperty($leaf);

            // add the main group to the root group
            $exportSpecificOptions->addProperty($structureOptions);
        }

        // begin Data options
        $dataOptions = new OptionsPropertyMainGroup(
            'data',
            __('Data creation options')
        );
        $dataOptions->setForce('structure');
        $leaf = new BoolPropertyItem(
            'truncate',
            __('Truncate table before insert')
        );
        $dataOptions->addProperty($leaf);

        // begin SQL Statements
        $subgroup = new OptionsPropertySubgroup();
        $leaf = new MessageOnlyPropertyItem(
            __('Instead of <code>INSERT</code> statements, use:')
        );
        $subgroup->setSubgroupHeader($leaf);

        $leaf = new BoolPropertyItem(
            'delayed',
            __('<code>INSERT DELAYED</code> statements')
        );
        $leaf->setDoc(
            [
                'manual_MySQL_Database_Administration',
                'insert_delayed',
            ]
        );
        $subgroup->addProperty($leaf);

        $leaf = new BoolPropertyItem(
            'ignore',
            __('<code>INSERT IGNORE</code> statements')
        );
        $leaf->setDoc(
            [
                'manual_MySQL_Database_Administration',
                'insert',
            ]
        );
        $subgroup->addProperty($leaf);
        $dataOptions->addProperty($subgroup);

        // Function to use when dumping dat
        $leaf = new SelectPropertyItem(
            'type',
            __('Function to use when dumping data:')
        );
        $leaf->setValues(
            [
                'INSERT' => 'INSERT',
                'UPDATE' => 'UPDATE',
                'REPLACE' => 'REPLACE',
            ]
        );
        $dataOptions->addProperty($leaf);

        /* Syntax to use when inserting data */
        $subgroup = new OptionsPropertySubgroup();
        $leaf = new MessageOnlyPropertyItem(
            null,
            __('Syntax to use when inserting data:')
        );
        $subgroup->setSubgroupHeader($leaf);
        $leaf = new RadioPropertyItem(
            'insert_syntax',
            __('<code>INSERT IGNORE</code> statements')
        );
        $leaf->setValues(
            [
                'complete' => __(
                    'include column names in every <code>INSERT</code> statement'
                    . ' <br> &nbsp; &nbsp; &nbsp; Example: <code>INSERT INTO'
                    . ' tbl_name (col_A,col_B,col_C) VALUES (1,2,3)</code>'
                ),
                'extended' => __(
                    'insert multiple rows in every <code>INSERT</code> statement'
                    . '<br> &nbsp; &nbsp; &nbsp; Example: <code>INSERT INTO'
                    . ' tbl_name VALUES (1,2,3), (4,5,6), (7,8,9)</code>'
                ),
                'both' => __(
                    'both of the above<br> &nbsp; &nbsp; &nbsp; Example:'
                    . ' <code>INSERT INTO tbl_name (col_A,col_B,col_C) VALUES'
                    . ' (1,2,3), (4,5,6), (7,8,9)</code>'
                ),
                'none' => __(
                    'neither of the above<br> &nbsp; &nbsp; &nbsp; Example:'
                    . ' <code>INSERT INTO tbl_name VALUES (1,2,3)</code>'
                ),
            ]
        );
        $subgroup->addProperty($leaf);
        $dataOptions->addProperty($subgroup);

        // Max length of query
        $leaf = new NumberPropertyItem(
            'max_query_size',
            __('Maximal length of created query')
        );
        $dataOptions->addProperty($leaf);

        // Dump binary columns in hexadecimal
        $leaf = new BoolPropertyItem(
            'hex_for_binary',
            __(
                'Dump binary columns in hexadecimal notation <i>(for example, "abc" becomes 0x616263)</i>'
            )
        );
        $dataOptions->addProperty($leaf);

        // Dump time in UTC
        $leaf = new BoolPropertyItem(
            'utc_time',
            __(
                'Dump TIMESTAMP columns in UTC <i>(enables TIMESTAMP columns'
                . ' to be dumped and reloaded between servers in different'
                . ' time zones)</i>'
            )
        );
        $dataOptions->addProperty($leaf);

        // add the main group to the root group
        $exportSpecificOptions->addProperty($dataOptions);

        // set the options for the export plugin property item
        $exportPluginProperties->setOptions($exportSpecificOptions);

        return $exportPluginProperties;
    }

    /**
     * Generates SQL for routines export
     *
     * @param string $db        Database
     * @param array  $aliases   Aliases of db/table/columns
     * @param string $type      Type of exported routine
     * @param string $name      Verbose name of exported routine
     * @param array  $routines  List of routines to export
     * @param string $delimiter Delimiter to use in SQL
     *
     * @return string SQL query
     */
    protected function exportRoutineSQL(
        $db,
        array $aliases,
        $type,
        $name,
        array $routines,
        $delimiter
    ) {
        global $crlf, $dbi;

        $text = $this->exportComment()
            . $this->exportComment($name)
            . $this->exportComment();

        $usedAlias = false;
        $procQuery = '';

        foreach ($routines as $routine) {
            if (! empty($GLOBALS['sql_drop_table'])) {
                $procQuery .= 'DROP ' . $type . ' IF EXISTS '
                    . Util::backquote($routine)
                    . $delimiter . $crlf;
            }

            $createQuery = $this->replaceWithAliases(
                $dbi->getDefinition($db, $type, $routine),
                $aliases,
                $db,
                '',
                $flag
            );
            // One warning per database
            if ($flag) {
                $usedAlias = true;
            }

            $procQuery .= $createQuery . $delimiter . $crlf . $crlf;
        }

        if ($usedAlias) {
            $text .= $this->exportComment(
                __('It appears your database uses routines;')
            )
            . $this->exportComment(
                __('alias export may not work reliably in all cases.')
            )
            . $this->exportComment();
        }

        $text .= $procQuery;

        return $text;
    }

    /**
     * Exports routines (procedures and functions)
     *
     * @param string $db      Database
     * @param array  $aliases Aliases of db/table/columns
     */
    public function exportRoutines($db, array $aliases = []): bool
    {
        global $crlf, $dbi;

        $dbAlias = $db;
        $this->initAlias($aliases, $dbAlias);

        $text = '';
        $delimiter = '$$';

        $procedureNames = $dbi->getProceduresOrFunctions($db, 'PROCEDURE');
        $functionNames = $dbi->getProceduresOrFunctions($db, 'FUNCTION');

        if ($procedureNames || $functionNames) {
            $text .= $crlf
                . 'DELIMITER ' . $delimiter . $crlf;

            if ($procedureNames) {
                $text .= $this->exportRoutineSQL(
                    $db,
                    $aliases,
                    'PROCEDURE',
                    __('Procedures'),
                    $procedureNames,
                    $delimiter
                );
            }

            if ($functionNames) {
                $text .= $this->exportRoutineSQL(
                    $db,
                    $aliases,
                    'FUNCTION',
                    __('Functions'),
                    $functionNames,
                    $delimiter
                );
            }

            $text .= 'DELIMITER ;' . $crlf;
        }

        if (! empty($text)) {
            return $this->export->outputHandler($text);
        }

        return false;
    }

    /**
     * Possibly outputs comment
     *
     * @param string $text Text of comment
     *
     * @return string The formatted comment
     */
    private function exportComment($text = '')
    {
        if (isset($GLOBALS['sql_include_comments']) && $GLOBALS['sql_include_comments']) {
            // see https://dev.mysql.com/doc/refman/5.0/en/ansi-diff-comments.html
            if (empty($text)) {
                return '--' . $GLOBALS['crlf'];
            }

            $lines = preg_split("/\\r\\n|\\r|\\n/", $text);
            if ($lines === false) {
                return '--' . $GLOBALS['crlf'];
            }

            $result = [];
            foreach ($lines as $line) {
                $result[] = '-- ' . $line . $GLOBALS['crlf'];
            }

            return implode('', $result);
        }

        return '';
    }

    /**
     * Possibly outputs CRLF
     *
     * @return string crlf or nothing
     */
    private function possibleCRLF()
    {
        if (isset($GLOBALS['sql_include_comments']) && $GLOBALS['sql_include_comments']) {
            return $GLOBALS['crlf'];
        }

        return '';
    }

    /**
     * Outputs export footer
     */
    public function exportFooter(): bool
    {
        global $crlf, $dbi;

        $foot = '';

        if (isset($GLOBALS['sql_disable_fk'])) {
            $foot .= 'SET FOREIGN_KEY_CHECKS=1;' . $crlf;
        }

        if (isset($GLOBALS['sql_use_transaction'])) {
            $foot .= 'COMMIT;' . $crlf;
        }

        // restore connection settings
        if ($this->sentCharset) {
            $foot .= $crlf
                . '/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;'
                . $crlf
                . '/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;'
                . $crlf
                . '/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;'
                . $crlf;
            $this->sentCharset = false;
        }

        /* Restore timezone */
        if (isset($GLOBALS['sql_utc_time']) && $GLOBALS['sql_utc_time']) {
            $dbi->query('SET time_zone = "' . $GLOBALS['old_tz'] . '"');
        }

        return $this->export->outputHandler($foot);
    }

    /**
     * Outputs export header. It is the first method to be called, so all
     * the required variables are initialized here.
     */
    public function exportHeader(): bool
    {
        global $crlf, $cfg, $dbi;

        if (isset($GLOBALS['sql_compatibility'])) {
            $tmpCompat = $GLOBALS['sql_compatibility'];
            if ($tmpCompat === 'NONE') {
                $tmpCompat = '';
            }

            $dbi->tryQuery('SET SQL_MODE="' . $tmpCompat . '"');
            unset($tmpCompat);
        }

        $head = $this->exportComment('phpMyAdmin SQL Dump')
            . $this->exportComment('version ' . Version::VERSION)
            . $this->exportComment('https://www.phpmyadmin.net/')
            . $this->exportComment();
        $hostString = __('Host:') . ' ' . $cfg['Server']['host'];
        if (! empty($cfg['Server']['port'])) {
            $hostString .= ':' . $cfg['Server']['port'];
        }

        $head .= $this->exportComment($hostString);
        $head .= $this->exportComment(
            __('Generation Time:') . ' '
            . Util::localisedDate()
        )
        . $this->exportComment(
            __('Server version:') . ' ' . $dbi->getVersionString()
        )
        . $this->exportComment(__('PHP Version:') . ' ' . PHP_VERSION)
        . $this->possibleCRLF();

        if (isset($GLOBALS['sql_header_comment']) && ! empty($GLOBALS['sql_header_comment'])) {
            // '\n' is not a newline (like "\n" would be), it's the characters
            // backslash and n, as explained on the export interface
            $lines = explode('\n', $GLOBALS['sql_header_comment']);
            $head .= $this->exportComment();
            foreach ($lines as $oneLine) {
                $head .= $this->exportComment($oneLine);
            }

            $head .= $this->exportComment();
        }

        if (isset($GLOBALS['sql_disable_fk'])) {
            $head .= 'SET FOREIGN_KEY_CHECKS=0;' . $crlf;
        }

        // We want exported AUTO_INCREMENT columns to have still same value,
        // do this only for recent MySQL exports
        if (! isset($GLOBALS['sql_compatibility']) || $GLOBALS['sql_compatibility'] === 'NONE') {
            $head .= 'SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO";' . $crlf;
        }

        if (isset($GLOBALS['sql_use_transaction'])) {
            $head .= 'START TRANSACTION;' . $crlf;
        }

        /* Change timezone if we should export timestamps in UTC */
        if (isset($GLOBALS['sql_utc_time']) && $GLOBALS['sql_utc_time']) {
            $head .= 'SET time_zone = "+00:00";' . $crlf;
            $GLOBALS['old_tz'] = $dbi
                ->fetchValue('SELECT @@session.time_zone');
            $dbi->query('SET time_zone = "+00:00"');
        }

        $head .= $this->possibleCRLF();

        if (! empty($GLOBALS['asfile'])) {
            // we are saving as file, therefore we provide charset information
            // so that a utility like the mysql client can interpret
            // the file correctly
            if (isset($GLOBALS['charset'], Charsets::$mysqlCharsetMap[$GLOBALS['charset']])) {
                // we got a charset from the export dialog
                $setNames = Charsets::$mysqlCharsetMap[$GLOBALS['charset']];
            } else {
                // by default we use the connection charset
                $setNames = Charsets::$mysqlCharsetMap['utf-8'];
            }

            if ($setNames === 'utf8' && $dbi->getVersion() > 50503) {
                $setNames = 'utf8mb4';
            }

            $head .= $crlf
                . '/*!40101 SET @OLD_CHARACTER_SET_CLIENT='
                . '@@CHARACTER_SET_CLIENT */;' . $crlf
                . '/*!40101 SET @OLD_CHARACTER_SET_RESULTS='
                . '@@CHARACTER_SET_RESULTS */;' . $crlf
                . '/*!40101 SET @OLD_COLLATION_CONNECTION='
                . '@@COLLATION_CONNECTION */;' . $crlf
                . '/*!40101 SET NAMES ' . $setNames . ' */;' . $crlf . $crlf;
            $this->sentCharset = true;
        }

        return $this->export->outputHandler($head);
    }

    /**
     * Outputs CREATE DATABASE statement
     *
     * @param string $db         Database name
     * @param string $exportType 'server', 'database', 'table'
     * @param string $dbAlias    Aliases of db
     */
    public function exportDBCreate($db, $exportType, $dbAlias = ''): bool
    {
        global $crlf, $dbi;

        if (empty($dbAlias)) {
            $dbAlias = $db;
        }

        if (isset($GLOBALS['sql_compatibility'])) {
            $compat = $GLOBALS['sql_compatibility'];
        } else {
            $compat = 'NONE';
        }

        if (isset($GLOBALS['sql_drop_database'])) {
            if (
                ! $this->export->outputHandler(
                    'DROP DATABASE IF EXISTS '
                    . Util::backquoteCompat(
                        $dbAlias,
                        $compat,
                        isset($GLOBALS['sql_backquotes'])
                    )
                    . ';' . $crlf
                )
            ) {
                return false;
            }
        }

        if ($exportType === 'database' && ! isset($GLOBALS['sql_create_database'])) {
            return true;
        }

        $createQuery = 'CREATE DATABASE IF NOT EXISTS '
            . Util::backquoteCompat($dbAlias, $compat, isset($GLOBALS['sql_backquotes']));
        $collation = $dbi->getDbCollation($db);
        if (mb_strpos($collation, '_')) {
            $createQuery .= ' DEFAULT CHARACTER SET '
                . mb_substr(
                    $collation,
                    0,
                    (int) mb_strpos($collation, '_')
                )
                . ' COLLATE ' . $collation;
        } else {
            $createQuery .= ' DEFAULT CHARACTER SET ' . $collation;
        }

        $createQuery .= ';' . $crlf;
        if (! $this->export->outputHandler($createQuery)) {
            return false;
        }

        return $this->exportUseStatement($dbAlias, $compat);
    }

    /**
     * Outputs USE statement
     *
     * @param string $db     db to use
     * @param string $compat sql compatibility
     */
    private function exportUseStatement($db, $compat): bool
    {
        global $crlf;

        if (isset($GLOBALS['sql_compatibility']) && $GLOBALS['sql_compatibility'] === 'NONE') {
            $result = $this->export->outputHandler(
                'USE '
                . Util::backquoteCompat(
                    $db,
                    $compat,
                    isset($GLOBALS['sql_backquotes'])
                )
                . ';' . $crlf
            );
        } else {
            $result = $this->export->outputHandler('USE ' . $db . ';' . $crlf);
        }

        return $result;
    }

    /**
     * Outputs database header
     *
     * @param string $db      Database name
     * @param string $dbAlias Alias of db
     */
    public function exportDBHeader($db, $dbAlias = ''): bool
    {
        if (empty($dbAlias)) {
            $dbAlias = $db;
        }

        if (isset($GLOBALS['sql_compatibility'])) {
            $compat = $GLOBALS['sql_compatibility'];
        } else {
            $compat = 'NONE';
        }

        $head = $this->exportComment()
            . $this->exportComment(
                __('Database:') . ' '
                . Util::backquoteCompat(
                    $dbAlias,
                    $compat,
                    isset($GLOBALS['sql_backquotes'])
                )
            )
            . $this->exportComment();

        return $this->export->outputHandler($head);
    }

    /**
     * Outputs database footer
     *
     * @param string $db Database name
     */
    public function exportDBFooter($db): bool
    {
        global $crlf;

        $result = true;

        //add indexes to the sql dump file
        if (isset($GLOBALS['sql_indexes'])) {
            $result = $this->export->outputHandler($GLOBALS['sql_indexes']);
            unset($GLOBALS['sql_indexes']);
        }

        //add auto increments to the sql dump file
        if (isset($GLOBALS['sql_auto_increments'])) {
            $result = $this->export->outputHandler($GLOBALS['sql_auto_increments']);
            unset($GLOBALS['sql_auto_increments']);
        }

        //add constraints to the sql dump file
        if (isset($GLOBALS['sql_constraints'])) {
            $result = $this->export->outputHandler($GLOBALS['sql_constraints']);
            unset($GLOBALS['sql_constraints']);
        }

        return $result;
    }

    /**
     * Exports events
     *
     * @param string $db Database
     */
    public function exportEvents($db): bool
    {
        global $crlf, $dbi;

        $text = '';
        $delimiter = '$$';

        $eventNames = $dbi->fetchResult(
            'SELECT EVENT_NAME FROM information_schema.EVENTS WHERE'
            . " EVENT_SCHEMA= '" . $dbi->escapeString($db)
            . "';"
        );

        if ($eventNames) {
            $text .= $crlf
                . 'DELIMITER ' . $delimiter . $crlf;

            $text .= $this->exportComment()
                . $this->exportComment(__('Events'))
                . $this->exportComment();

            foreach ($eventNames as $eventName) {
                if (! empty($GLOBALS['sql_drop_table'])) {
                    $text .= 'DROP EVENT IF EXISTS '
                        . Util::backquote($eventName)
                        . $delimiter . $crlf;
                }

                $text .= $dbi->getDefinition($db, 'EVENT', $eventName)
                    . $delimiter . $crlf . $crlf;
            }

            $text .= 'DELIMITER ;' . $crlf;
        }

        if (! empty($text)) {
            return $this->export->outputHandler($text);
        }

        return false;
    }

    /**
     * Exports metadata from Configuration Storage
     *
     * @param string       $db            database being exported
     * @param string|array $tables        table(s) being exported
     * @param array        $metadataTypes types of metadata to export
     */
    public function exportMetadata(
        $db,
        $tables,
        array $metadataTypes
    ): bool {
        $cfgRelation = $this->relation->getRelationsParam();
        if (! isset($cfgRelation['db'])) {
            return true;
        }

        $comment = $this->possibleCRLF()
            . $this->possibleCRLF()
            . $this->exportComment()
            . $this->exportComment(__('Metadata'))
            . $this->exportComment();
        if (! $this->export->outputHandler($comment)) {
            return false;
        }

        if (! $this->exportUseStatement($cfgRelation['db'], $GLOBALS['sql_compatibility'])) {
            return false;
        }

        $r = 1;
        if (is_array($tables)) {
            // export metadata for each table
            foreach ($tables as $table) {
                $r &= (int) $this->exportConfigurationMetadata($db, $table, $metadataTypes);
            }

            // export metadata for the database
            $r &= (int) $this->exportConfigurationMetadata($db, null, $metadataTypes);
        } else {
            // export metadata for single table
            $r &= (int) $this->exportConfigurationMetadata($db, $tables, $metadataTypes);
        }

        return (bool) $r;
    }

    /**
     * Exports metadata from Configuration Storage
     *
     * @param string      $db            database being exported
     * @param string|null $table         table being exported
     * @param array       $metadataTypes types of metadata to export
     */
    private function exportConfigurationMetadata(
        $db,
        $table,
        array $metadataTypes
    ): bool {
        global $dbi;

        $cfgRelation = $this->relation->getRelationsParam();

        if (isset($table)) {
            $types = [
                'column_info' => 'db_name',
                'table_uiprefs' => 'db_name',
                'tracking' => 'db_name',
            ];
        } else {
            $types = [
                'bookmark' => 'dbase',
                'relation' => 'master_db',
                'pdf_pages' => 'db_name',
                'savedsearches' => 'db_name',
                'central_columns' => 'db_name',
            ];
        }

        $aliases = [];

        $comment = $this->possibleCRLF()
            . $this->exportComment();

        if (isset($table)) {
            $comment .= $this->exportComment(
                sprintf(
                    __('Metadata for table %s'),
                    $table
                )
            );
        } else {
            $comment .= $this->exportComment(
                sprintf(
                    __('Metadata for database %s'),
                    $db
                )
            );
        }

        $comment .= $this->exportComment();

        if (! $this->export->outputHandler($comment)) {
            return false;
        }

        foreach ($types as $type => $dbNameColumn) {
            if (! in_array($type, $metadataTypes) || ! isset($cfgRelation[$type])) {
                continue;
            }

            // special case, designer pages and their coordinates
            if ($type === 'pdf_pages') {
                $sqlQuery = 'SELECT `page_nr`, `page_descr` FROM '
                    . Util::backquote($cfgRelation['db'])
                    . '.' . Util::backquote($cfgRelation[$type])
                    . ' WHERE ' . Util::backquote($dbNameColumn)
                    . " = '" . $dbi->escapeString($db) . "'";

                $result = $dbi->fetchResult($sqlQuery, 'page_nr', 'page_descr');

                foreach ($result as $page => $name) {
                    // insert row for pdf_page
                    $sqlQueryRow = 'SELECT `db_name`, `page_descr` FROM '
                        . Util::backquote($cfgRelation['db'])
                        . '.' . Util::backquote($cfgRelation[$type])
                        . ' WHERE ' . Util::backquote($dbNameColumn)
                        . " = '" . $dbi->escapeString($db) . "'"
                        . " AND `page_nr` = '" . intval($page) . "'";

                    if (
                        ! $this->exportData(
                            $cfgRelation['db'],
                            $cfgRelation[$type],
                            $GLOBALS['crlf'],
                            '',
                            $sqlQueryRow,
                            $aliases
                        )
                    ) {
                        return false;
                    }

                    $lastPage = $GLOBALS['crlf']
                        . 'SET @LAST_PAGE = LAST_INSERT_ID();'
                        . $GLOBALS['crlf'];
                    if (! $this->export->outputHandler($lastPage)) {
                        return false;
                    }

                    $sqlQueryCoords = 'SELECT `db_name`, `table_name`, '
                        . "'@LAST_PAGE' AS `pdf_page_number`, `x`, `y` FROM "
                        . Util::backquote($cfgRelation['db'])
                        . '.' . Util::backquote($cfgRelation['table_coords'])
                        . " WHERE `pdf_page_number` = '" . $page . "'";

                    $GLOBALS['exporting_metadata'] = true;
                    if (
                        ! $this->exportData(
                            $cfgRelation['db'],
                            $cfgRelation['table_coords'],
                            $GLOBALS['crlf'],
                            '',
                            $sqlQueryCoords,
                            $aliases
                        )
                    ) {
                        $GLOBALS['exporting_metadata'] = false;

                        return false;
                    }

                    $GLOBALS['exporting_metadata'] = false;
                }

                continue;
            }

            // remove auto_incrementing id field for some tables
            if ($type === 'bookmark') {
                $sqlQuery = 'SELECT `dbase`, `user`, `label`, `query` FROM ';
            } elseif ($type === 'column_info') {
                $sqlQuery = 'SELECT `db_name`, `table_name`, `column_name`,'
                    . ' `comment`, `mimetype`, `transformation`,'
                    . ' `transformation_options`, `input_transformation`,'
                    . ' `input_transformation_options` FROM';
            } elseif ($type === 'savedsearches') {
                $sqlQuery = 'SELECT `username`, `db_name`, `search_name`, `search_data` FROM';
            } else {
                $sqlQuery = 'SELECT * FROM ';
            }

            $sqlQuery .= Util::backquote($cfgRelation['db'])
                . '.' . Util::backquote($cfgRelation[$type])
                . ' WHERE ' . Util::backquote($dbNameColumn)
                . " = '" . $dbi->escapeString($db) . "'";
            if (isset($table)) {
                $sqlQuery .= " AND `table_name` = '"
                    . $dbi->escapeString($table) . "'";
            }

            if (
                ! $this->exportData(
                    $cfgRelation['db'],
                    $cfgRelation[$type],
                    $GLOBALS['crlf'],
                    '',
                    $sqlQuery,
                    $aliases
                )
            ) {
                return false;
            }
        }

        return true;
    }

    /**
     * Returns a stand-in CREATE definition to resolve view dependencies
     *
     * @param string $db      the database name
     * @param string $view    the view name
     * @param string $crlf    the end of line sequence
     * @param array  $aliases Aliases of db/table/columns
     *
     * @return string resulting definition
     */
    public function getTableDefStandIn($db, $view, $crlf, $aliases = [])
    {
        global $dbi;

        $dbAlias = $db;
        $viewAlias = $view;
        $this->initAlias($aliases, $dbAlias, $viewAlias);
        $createQuery = '';
        if (! empty($GLOBALS['sql_drop_table'])) {
            $createQuery .= 'DROP VIEW IF EXISTS '
                . Util::backquote($viewAlias)
                . ';' . $crlf;
        }

        $createQuery .= 'CREATE TABLE ';

        if (isset($GLOBALS['sql_if_not_exists']) && $GLOBALS['sql_if_not_exists']) {
            $createQuery .= 'IF NOT EXISTS ';
        }

        $createQuery .= Util::backquote($viewAlias) . ' (' . $crlf;
        $tmp = [];
        $columns = $dbi->getColumnsFull($db, $view);
        foreach ($columns as $columnName => $definition) {
            $colAlias = $columnName;
            if (! empty($aliases[$db]['tables'][$view]['columns'][$colAlias])) {
                $colAlias = $aliases[$db]['tables'][$view]['columns'][$colAlias];
            }

            $tmp[] = Util::backquote($colAlias) . ' ' .
                $definition['Type'] . $crlf;
        }

        return $createQuery . implode(',', $tmp) . ');' . $crlf;
    }

    /**
     * Returns CREATE definition that matches $view's structure
     *
     * @param string $db           the database name
     * @param string $view         the view name
     * @param string $crlf         the end of line sequence
     * @param bool   $addSemicolon whether to add semicolon and end-of-line at
     *                              the end
     * @param array  $aliases      Aliases of db/table/columns
     *
     * @return string resulting schema
     */
    private function getTableDefForView(
        $db,
        $view,
        $crlf,
        $addSemicolon = true,
        array $aliases = []
    ) {
        global $dbi;

        $dbAlias = $db;
        $viewAlias = $view;
        $this->initAlias($aliases, $dbAlias, $viewAlias);
        $createQuery = 'CREATE TABLE';
        if (isset($GLOBALS['sql_if_not_exists'])) {
            $createQuery .= ' IF NOT EXISTS ';
        }

        $createQuery .= Util::backquote($viewAlias) . '(' . $crlf;

        $columns = $dbi->getColumns($db, $view, null, true);

        $firstCol = true;
        foreach ($columns as $column) {
            $colAlias = $column['Field'];
            if (! empty($aliases[$db]['tables'][$view]['columns'][$colAlias])) {
                $colAlias = $aliases[$db]['tables'][$view]['columns'][$colAlias];
            }

            $extractedColumnspec = Util::extractColumnSpec($column['Type']);

            if (! $firstCol) {
                $createQuery .= ',' . $crlf;
            }

            $createQuery .= '    ' . Util::backquote($colAlias);
            $createQuery .= ' ' . $column['Type'];
            if ($extractedColumnspec['can_contain_collation'] && ! empty($column['Collation'])) {
                $createQuery .= ' COLLATE ' . $column['Collation'];
            }

            if ($column['Null'] === 'NO') {
                $createQuery .= ' NOT NULL';
            }

            if (isset($column['Default'])) {
                $createQuery .= " DEFAULT '"
                    . $dbi->escapeString($column['Default']) . "'";
            } else {
                if ($column['Null'] === 'YES') {
                    $createQuery .= ' DEFAULT NULL';
                }
            }

            if (! empty($column['Comment'])) {
                $createQuery .= " COMMENT '"
                    . $dbi->escapeString($column['Comment']) . "'";
            }

            $firstCol = false;
        }

        $createQuery .= $crlf . ')' . ($addSemicolon ? ';' : '') . $crlf;

        if (isset($GLOBALS['sql_compatibility'])) {
            $compat = $GLOBALS['sql_compatibility'];
        } else {
            $compat = 'NONE';
        }

        if ($compat === 'MSSQL') {
            $createQuery = $this->makeCreateTableMSSQLCompatible($createQuery);
        }

        return $createQuery;
    }

    /**
     * Returns $table's CREATE definition
     *
     * @param string $db                      the database name
     * @param string $table                   the table name
     * @param string $crlf                    the end of line sequence
     * @param string $errorUrl                the url to go back in case
     *                                         of error
     * @param bool   $showDates               whether to include creation/
     *                                         update/check dates
     * @param bool   $addSemicolon            whether to add semicolon and
     *                                         end-of-line at the end
     * @param bool   $view                    whether we're handling a view
     * @param bool   $updateIndexesIncrements whether we need to update
     *                                          two global variables
     * @param array  $aliases                 Aliases of db/table/columns
     *
     * @return string resulting schema
     */
    public function getTableDef(
        $db,
        $table,
        $crlf,
        $errorUrl,
        $showDates = false,
        $addSemicolon = true,
        $view = false,
        $updateIndexesIncrements = true,
        array $aliases = []
    ) {
        global $sql_drop_table, $sql_backquotes, $sql_constraints,
               $sql_constraints_query, $sql_indexes, $sql_indexes_query,
               $sql_auto_increments, $sql_drop_foreign_keys, $dbi;

        $dbAlias = $db;
        $tableAlias = $table;
        $this->initAlias($aliases, $dbAlias, $tableAlias);

        $schemaCreate = '';
        $autoIncrement = '';
        $newCrlf = $crlf;

        if (isset($GLOBALS['sql_compatibility'])) {
            $compat = $GLOBALS['sql_compatibility'];
        } else {
            $compat = 'NONE';
        }

        // need to use PhpMyAdmin\DatabaseInterface::QUERY_STORE
        // with $dbi->numRows() in mysqli
        $result = $dbi->tryQuery(
            'SHOW TABLE STATUS FROM ' . Util::backquote($db)
            . ' WHERE Name = \'' . $dbi->escapeString((string) $table) . '\'',
            DatabaseInterface::CONNECT_USER,
            DatabaseInterface::QUERY_STORE
        );
        if ($result != false) {
            if ($dbi->numRows($result) > 0) {
                $tmpres = $dbi->fetchAssoc($result);

                // Here we optionally add the AUTO_INCREMENT next value,
                // but starting with MySQL 5.0.24, the clause is already included
                // in SHOW CREATE TABLE so we'll remove it below
                if (isset($GLOBALS['sql_auto_increment']) && ! empty($tmpres['Auto_increment'])) {
                    $autoIncrement .= ' AUTO_INCREMENT='
                        . $tmpres['Auto_increment'] . ' ';
                }

                if ($showDates && isset($tmpres['Create_time']) && ! empty($tmpres['Create_time'])) {
                    $schemaCreate .= $this->exportComment(
                        __('Creation:') . ' '
                        . Util::localisedDate(
                            strtotime($tmpres['Create_time'])
                        )
                    );
                    $newCrlf = $this->exportComment() . $crlf;
                }

                if ($showDates && isset($tmpres['Update_time']) && ! empty($tmpres['Update_time'])) {
                    $schemaCreate .= $this->exportComment(
                        __('Last update:') . ' '
                        . Util::localisedDate(
                            strtotime($tmpres['Update_time'])
                        )
                    );
                    $newCrlf = $this->exportComment() . $crlf;
                }

                if ($showDates && isset($tmpres['Check_time']) && ! empty($tmpres['Check_time'])) {
                    $schemaCreate .= $this->exportComment(
                        __('Last check:') . ' '
                        . Util::localisedDate(
                            strtotime($tmpres['Check_time'])
                        )
                    );
                    $newCrlf = $this->exportComment() . $crlf;
                }
            }

            $dbi->freeResult($result);
        }

        $schemaCreate .= $newCrlf;

        if (! empty($sql_drop_table) && $dbi->getTable($db, $table)->isView()) {
            $schemaCreate .= 'DROP VIEW IF EXISTS '
                . Util::backquoteCompat($tableAlias, 'NONE', $sql_backquotes) . ';'
                . $crlf;
        }

        // no need to generate a DROP VIEW here, it was done earlier
        if (! empty($sql_drop_table) && ! $dbi->getTable($db, $table)->isView()) {
            $schemaCreate .= 'DROP TABLE IF EXISTS '
                . Util::backquoteCompat($tableAlias, 'NONE', $sql_backquotes) . ';'
                . $crlf;
        }

        // Complete table dump,
        // Whether to quote table and column names or not
        if ($sql_backquotes) {
            $dbi->query('SET SQL_QUOTE_SHOW_CREATE = 1');
        } else {
            $dbi->query('SET SQL_QUOTE_SHOW_CREATE = 0');
        }

        // I don't see the reason why this unbuffered query could cause problems,
        // because SHOW CREATE TABLE returns only one row, and we free the
        // results below. Nonetheless, we got 2 user reports about this
        // (see bug 1562533) so I removed the unbuffered mode.
        // $result = $dbi->query('SHOW CREATE TABLE ' . backquote($db)
        // . '.' . backquote($table), null, DatabaseInterface::QUERY_UNBUFFERED);
        //
        // Note: SHOW CREATE TABLE, at least in MySQL 5.1.23, does not
        // produce a displayable result for the default value…