There are many tools that are used with databases, each one with a focus on some capabilities. To interact with a database to execute queries, make changes to the database, observe what is happening in the database, and so on, there are client tools such as psql and pgAdmin (pgAdmin III). These do not have a web interface and need to be installed on the machine from which the database will be accessed. Similar capabilities are provided by phpPgAdmin, which provides a web interface.
Then, there are products such as TOra (http://torasql.com/). The key difference here is that TOra is a tool that works with a few databases, whereas pgAdmin has a focus on PostgreSQL.
Some tools focus on database administration activities (taking backups, restoring from backups, monitoring performance, killing sessions, monitoring memory usage, and space utilization). Some others focus on executing queries or scripts, describing tables (mostly developer activity).