Cache and Raid performance. One of the key limitations of spinning disk hardware is the use of a physical reading armature and the time this takes to move across the surface of a diskâs platter to the required data blocks.
Constraints are part of a database schema definition. A constraint is usually associated with a table and is created with a CREATE CONSTRAINT or CREATE ASSERTION SQL statement. They define certain properties that data in a database must comply with.
In this CREATE TABLE statement, integrity constraints are defined on several columns of the table, and transparent data encryption is defined on one (ssn). Integrity constraints are discussed in Managing Integrity Constraints, and transparent data encryption is discussed in Oracle Database Security Guide.