Lightweight Databases

`DBM`

Perl's tie feature is a generalization of DBM files
- (DBM is short for Data Base Manager, I think)
Basic idea: A Perl data structure is backed by a disk file
- Reading the data structures reads the file
- Modifying the data structures writes the file
This first appeared in perl 3

        dbmopen %hash, $filename, $permissions;

        dbmclose %hash;