It is important that you read through this section to familiarize yourself with the concepts and terminology to be used throughout this manual. All memory structures exist in the main memory of the computers that constitute the database system. Processes are jobs or tasks that work in the memory of these computers. For example, memory is used to store program code being executed and data that is shared among users. The SGA is allocated when an instance starts and deallocated when the instance shuts down.
Some operating systems use the terms job or task.
The user process also manages the communication with the server processes. User processes communicate with the server processes through the program interface. Structures and the data contained within them can be manipulated by operations. Operations Operations are clearly defined actions that allow users to manipulate the data and structures of a database. The operations on a database must adhere to a pre-defined set of integrity rules.