mysqldiff is a Perl script which compares the data structures (i.e. table definitions) of two MySQL databases and returns the differences as a sequence of MySQL commands suitable for piping into mysql which will transform the structure of the first database to be identical to that of the second (c.f. diff and patch). Database structures can be compared whether they are files containing table definitions or existing databases, local or remote.
The DBIWrapper is a Perl Module that provides for easier access to databases using DBI. It supports MySQL, PostgreSQL, and ODBC DBD modules. High level methods for reading, writing, commiting, and rolling back transactions to the database are provided. XML or DBI data structures can be used.
Config::Natural is a Perl module that can read generic configuration files with a simple but very flexible syntax. It has very few constraints on the data, and has support for multi-line values and nested lists. Its object oriented API is compatible with modules like CGI or HTML::Template, and it can be safely associated with the latter.
dbMan is a complex SQL monitor for common database systems (PgSQL, Oracle, MySQL etc.). It's based on Perl and DBI interfaces. Features include a command history buffer, tab completion, editing Oracle objects, simultaneous connections, SQL help, importing and exporting of tables, Oracle explain plan, and more. dbMan is made as a simple kernel and many extension modules, and you can make your modules with a simple HOWTO.