Similar to what TheHobbit said: if you're able to use or install DBI you might want to look at DBD::SQLite. It's a database driver and database library all rolled into one. It's very fast and you can use normal SQL statements just as if you were using MySQL or other RDBMS.

You might also look into using some sort of DBM storage and MLDBM. Just use your existing IDs as keys (e.g., 'pupil1', 'pupil2') and store the information in a hash.

Chris
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