Uhura is a Web console for databases. It works with MySQL, PostgreSQL, and FirebirdSQL. It presents trees that let you browse databases, tables, columns, constraints, triggers, views, and procs. It has panels for history and fragments. Its editor features autocompletion and autoindenting. It is easy to install.
mysql-diff is a commandline database structure comparator. It compares the structure of two databases. It currently works with MySQL. A database can be specified as an SQL script or as an URL to a running database. So the tool can compare two scripts, two live databases, or a database and a script. The tool outputs SQL DDL script that can be used to convert one schema to another.