An Oracle database, or Oracle DB, is a type of database developed by Oracle and designed for use with Oracle software. It has schemas and tables, like most other databases, but its structure is optimized to work best with Oracle software. Such software includes the Oracle HRMS system, the Oracle Manufacturing ERP system, and the Oracle WebCenter Content (electronic document archival) system.
Additional tables can be added to an Oracle database if desired, and additional columns can be added to tables in the database. Accessing data in an Oracle database requires the use of the SQL programming language. SQL is a standard programming language for databases, and for Oracle databases, the SQL syntax can be a little different than the syntax for other types of databases. However, the general structure of "Oracle SQL" is relatively the same as SQL syntax for other databases.
The size of an Oracle database varies depending on its use, but it can become very large, being hundreds of gigabytes, or even terabytes, in size.
Using an Oracle database requires licensing from Oracle. The licensing costs vary by use case and can be expensive, costing several hundred thousand dollars or more. Due to the costs, Oracle databases are more often used by larger companies that can afford the higher costs.