Databases
An Ingres installation (or instance) may support many databases, each being owned by any user known to the installation. The installation will allow many databases to be available concurrently. The number available is a configurable quantity. Note this simply restricts the number of databases available at any instant, and many more databases may be created.
On creation of an Ingres Server installation, the databases named "iidbdb" and "imadb" are created. These databases are owned by the user "$ingres". The database iidbdb is also known as the "Master Catalog database", and it contains many tables specific to the management of the installation itself. The database imadb is the Ingres Management Architecture database, and it also contains many registered objects useful for management of the installation.
Of particular note is that databases do not need to be "pre-sized". Each database in the installation is permitted to grow as large as the available disk space will permit.
Read more about this topic: Ingres (database)