system/Database/BaseUtils.php
public function backup($params = [])
	{
		// If the parameters have not been submitted as an
		// array then we know that it is simply the table
		// name, which is a valid short cut.
		if (is_string($params))
		{
			$params = ['tables' => $params];
		}

		// Set up our default preferences
		$prefs = [
			'tables'             => [],
			'ignore'             => [],
			'filename'           => '',
			'format'             => 'gzip', // gzip, zip, txt
			'add_drop'           => true,
			'add_insert'         => true,
			'newline'            => "\n",
			'foreign_key_checks' => true,
		];

		// Did the user submit any preferences? If so set them....
		if (! empty($params))
		{
			foreach ($prefs as $key => $val)
			{
				if (isset($params[$key]))
				{
					$prefs[$key] = $params[$key];
				}
			}
		}

		// Are we backing up a complete database or individual tables?
		// If no table names were submitted we'll fetch the entire table list
		if (empty($prefs['tables']))
		{
			$prefs['tables'] = $this->db->listTables();
		}

		// Validate the format
		if (! in_array($prefs['format'], ['gzip', 'zip', 'txt'], true))
		{
			$prefs['format'] = 'txt';
		}

		// Is the encoder supported? If not, we'll either issue an
		// error or use plain text depending on the debug settings
		if (($prefs['format'] === 'gzip' && ! function_exists('gzencode'))
			|| ( $prefs['format'] === 'zip' && ! function_exists('gzcompress')))
		{
			if ($this->db->DBDebug)
			{
				throw new DatabaseException('The file compression format you chose is not supported by your server.');
			}

			$prefs['format'] = 'txt';
		}

		// Was a Zip file requested?
		if ($prefs['format'] === 'zip')
		{
			// Set the filename if not provided (only needed with Zip files)
			if ($prefs['filename'] === '')
			{
				$prefs['filename'] = (count($prefs['tables']) === 1 ? $prefs['tables'] : $this->db->database)
					. date('Y-m-d_H-i', time()) . '.sql';
			}
			else
			{
				// If they included the .zip file extension we'll remove it
				if (preg_match('|.+?\.zip$|', $prefs['filename']))
				{
					$prefs['filename'] = str_replace('.zip', '', $prefs['filename']);
				}

				// Tack on the ".sql" file extension if needed
				if (! preg_match('|.+?\.sql$|', $prefs['filename']))
				{
					$prefs['filename'] .= '.sql';
				}
			}

			// Load the Zip class and output it
			//          $CI =& get_instance();
			//          $CI->load->library('zip');
			//          $CI->zip->add_data($prefs['filename'], $this->_backup($prefs));
			//          return $CI->zip->get_zip();
		}
		elseif ($prefs['format'] === 'txt') // Was a text file requested?
		{
			return $this->_backup($prefs);
		}
		elseif ($prefs['format'] === 'gzip') // Was a Gzip file requested?
		{
			return gzencode($this->_backup($prefs));
		}

		return;
	}
public function backup($params = [])
	{
		// If the parameters have not been submitted as an
		// array then we know that it is simply the table
		// name, which is a valid short cut.
		if (is_string($params))
		{
			$params = ['tables' => $params];
		}

		// Set up our default preferences
		$prefs = [
			'tables'             => [],
			'ignore'             => [],
			'filename'           => '',
			'format'             => 'gzip', // gzip, zip, txt
			'add_drop'           => true,
			'add_insert'         => true,
			'newline'            => "\n",
			'foreign_key_checks' => true,
		];

		// Did the user submit any preferences? If so set them....
		if (! empty($params))
		{
			foreach ($prefs as $key => $val)
			{
				if (isset($params[$key]))
				{
					$prefs[$key] = $params[$key];
				}
			}
		}

		// Are we backing up a complete database or individual tables?
		// If no table names were submitted we'll fetch the entire table list
		if (empty($prefs['tables']))
		{
			$prefs['tables'] = $this->db->listTables();
		}

		// Validate the format
		if (! in_array($prefs['format'], ['gzip', 'zip', 'txt'], true))
		{
			$prefs['format'] = 'txt';
		}

		// Is the encoder supported? If not, we'll either issue an
		// error or use plain text depending on the debug settings
		if (($prefs['format'] === 'gzip' && ! function_exists('gzencode'))
			|| ( $prefs['format'] === 'zip' && ! function_exists('gzcompress')))
		{
			if ($this->db->DBDebug)
			{
				throw new DatabaseException('The file compression format you chose is not supported by your server.');
			}

			$prefs['format'] = 'txt';
		}

		// Was a Zip file requested?
		if ($prefs['format'] === 'zip')
		{
			// Set the filename if not provided (only needed with Zip files)
			if ($prefs['filename'] === '')
			{
				$prefs['filename'] = (count($prefs['tables']) === 1 ? $prefs['tables'] : $this->db->database)
					. date('Y-m-d_H-i', time()) . '.sql';
			}
			else
			{
				// If they included the .zip file extension we'll remove it
				if (preg_match('|.+?\.zip$|', $prefs['filename']))
				{
					$prefs['filename'] = str_replace('.zip', '', $prefs['filename']);
				}

				// Tack on the ".sql" file extension if needed
				if (! preg_match('|.+?\.sql$|', $prefs['filename']))
				{
					$prefs['filename'] .= '.sql';
				}
			}

			// Load the Zip class and output it
			//          $CI =& get_instance();
			//          $CI->load->library('zip');
			//          $CI->zip->add_data($prefs['filename'], $this->_backup($prefs));
			//          return $CI->zip->get_zip();
		}
		elseif ($prefs['format'] === 'txt') // Was a text file requested?
		{
			return $this->_backup($prefs);
		}
		elseif ($prefs['format'] === 'gzip') // Was a Gzip file requested?
		{
			return gzencode($this->_backup($prefs));
		}

		return;
	}
Database Backup

@param  array|string $params
@return mixed
@throws \CodeIgniter\Database\Exceptions\DatabaseException