What is the Difference Between Database and Instance?

The main difference between a database and an instance lies in their definition and function. A database refers to the data stored on disk, usually in operating system files or raw files under Unix. On the other hand, an instance is composed of a System Global Area (SGA) memory and background processes that manage the database files.

Key differences between database and instance include:

• Data Storage: The database stores the actual data, while the instance is responsible for managing and manipulating the data in the database.
• Memory and Processes: An instance is a set of memory structures and processes that work together to manage the database files.
• Access: Users connect to the instance to access the data in the database.

In summary, the database is the data itself, stored on disk, while the instance is the software and memory that manages and manipulates the data in the database.

Comparative Table: Database vs Instance

Here is a table highlighting the differences between a database and an instance:

In summary, a database is a collection of data stored on disk and consists of tables that store structured data, while an instance is a set of background processes and shared memory that manages and provides access to databases. A single instance can manage multiple databases, and each database can be managed by only one instance at a time.