A production database from which one or more standby databases is created and maintained. Every standby database is associated with one and only one primary database. A single primary database can, however, support multiple standby databases. The Data Guard broker monitor (DMON) maintains the master copy of the binary configuration file with the primary database, ensuring that each standby database's copy of the file is kept up to date as changes are made. The broker refers to this database using the value in the DB_UNIQUE_NAME initialization parameter which is defined to be globally unique.

A database that stores biomolecular sequences (protein or nucleic acid) and associated annotation information (organism, species, function, mutations linked to particular diseases, functional/structural patterns, bibliographic, etc.).

The database that contains the data to be replicated to another database (the standby database) through a replication system. The primary database is the database that is the source of replicated data in a replication system. Sometimes called the active database. Contrast with standby database. See also primary data.