Question

Suppose a row (several rows) or table in database. Can I backup them, to restore as quick as possible only them if the rows/table will be corrupted.

thank you in advance!

Answer 1

I use the following perl-script to backup my databases:

#!/usr/bin/perl
use strict;
use DBI;
my $dbh = DBI->connect( "dbi:mysql:database=;mysql_client_found_rows=0;host=your.database.host", "username", "password", {RaiseError => 1});
my $databases = $dbh->selectcol_arrayref('SHOW databases;');
foreach my $t (@{$databases}) {
   system('/usr/local/bin/mysqldump -h your.database.host --add-drop-database --add-drop-table --add-locks --extended-insert=false --databases --allow-keywords -c -e -f -u username  --password=password \''.$t.'\' > /path/to/backupfiles/'.$t.'.sql');
   print "$t done\n";
   sleep(2);
}

The mysql-dump command is:

/usr/local/bin/mysqldump -h your.database.host –add-drop-database –add-drop-table –add-locks –extended-insert=false –databases –allow-keywords -c -e -f -u username –password=password ‘databasename’ > /path/to/backupfiles/databasename.sql

The result are single insert-statements for the whole table. You have to extract the lines you want to restore. Since you do not know which row will be damaged, you’ll need them all. To restore a single row, just find it in the backup-file and execute the command.

I found it very difficult to deal with a backup file, that contains several databases. That’s the reason to write this little script and backup each database into a single file.

You can alter the script easily, to dump each table into a single backup-file if needed.