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.
SQL Constraints. SQL constraints are used to specify rules for the data in a table. If there is any violation between the constraint and the data action, the action is aborted by the constraint.Constraints can be specified when the table is created (inside the CREATE TABLE statement) or after the table is created (inside the ALTER TABLE statement).f there is any violation between the constraint and the data action, the action is aborted by the constraint. Constraints can be specified when the table is created (inside the CREATE TABLE statement) or after the table is created (inside the ALTER TABLE statement).