求段php导出mysql备份数据的代码

function sqldumptable($table, $fp=0) {
         global $DB;         $tabledump = "DROP TABLE IF EXISTS $table;\n";
         $tabledump .= "CREATE TABLE $table (\n";         $firstfield=1;         $fields = $DB->query("SHOW FIELDS FROM $table");
         while ($field = $DB->fetch_array($fields)) {
                if (!$firstfield) {
                    $tabledump .= ",\n";
                } else {
                    $firstfield=0;
                }
                $tabledump .= "   $field[Field] $field[Type]";
                if (!empty($field["Default"])) {
                    $tabledump .= " DEFAULT '$field[Default]'";
                }
                if ($field['Null'] != "YES") {
                    $tabledump .= " NOT NULL";
                }
                if ($field['Extra'] != "") {
                    $tabledump .= " $field[Extra]";
                }
         }
         $DB->free_result($fields);         $keys = $DB->query("SHOW KEYS FROM $table");
         while ($key = $DB->fetch_array($keys)) {
                $kname=$key['Key_name'];
                if ($kname != "PRIMARY" and $key['Non_unique'] == 0) {
                  $kname="UNIQUE|$kname";
                }
                if(!is_array($index[$kname])) {
                  $index[$kname] = array();
                }
                $index[$kname][] = $key['Column_name'];
         }
         $DB->free_result($keys);         while(list($kname, $columns) = @each($index)){
               $tabledump .= ",\n";
               $colnames=implode($columns,",");               if ($kname == "PRIMARY") {
                  $tabledump .= "   PRIMARY KEY ($colnames)";
               } else {
                  if (substr($kname,0,6) == "UNIQUE") {
                      $kname=substr($kname,7);
                  }
                  $tabledump .= "   KEY $kname ($colnames)";
               }
         }         $tabledump .= "\n);\n\n";
         if ($fp) {
             fwrite($fp,$tabledump);
         } else {
             echo $tabledump;
         }         $rows = $DB->query("SELECT * FROM $table");
         $numfields = mysql_num_fields($rows);
         while ($row = $DB->fetch_array($rows)) {
                $tabledump = "INSERT INTO $table VALUES(";                $fieldcounter=-1;
                $firstfield=1;
                while (++$fieldcounter<$numfields) {
                       if (!$firstfield) {
                           $tabledump.=", ";
                       } else {
                           $firstfield=0;
                       }                       if (!isset($row[$fieldcounter])) {
                           $tabledump .= "NULL";
                       } else {
                           $tabledump .= "'".mysql_escape_string($row[$fieldcounter])."'";
                       }
                }                $tabledump .= ");\n";                if ($fp) {
                    fwrite($fp,$tabledump);
                } else {
                    echo $tabledump;
                }
         }
         $DB->free_result($rows);
}