What does SID refer to in Oracle?

In Oracle, SID stands for System Identifier.

The SID is a unique string used to identify a specific Oracle database instance. Each Oracle database instance has a unique SID, which is used to differentiate between multiple database instances.

When starting the Oracle database, it is necessary to specify the SID of the database instance that you want to start. Using the SID, you can connect to the specified database instance and perform operations such as querying, inserting, updating, etc.

SID is also utilized for carrying out management tasks in Oracle databases, such as backup and recovery, performance tuning, and so on.

In summary, SID is a unique identifier used in Oracle databases to distinguish and identify different database instances.