Introduction to database management systems

The information rule 

The information rule simply requires all information in databases to be represented only one way.

The guaranteed access rule 

All data must be accessible. This rule is essentially a restatement of the fundamental requirement for primary keys.

Systematic treatment of null values 

The DBMS is required to support a representation of "missing information and inapplicable information" that is systematic, distinct from all regular values and independent of data type.

Active online catalog 

The system is required to support an online, inline, relational catalog that is accessible to authorized users by means of their regular query language.

Comprehensive data sublanguage rule 

The system must support a least one relational language that has a linear syntax

  (b) Can be used both interactively and within application programs

  (c) Supports data definition operations (including view definitions)

View updating rule 

All views that are theoretically updatable must be updatable by the system.

High-level insert, update, and delete 

The system must support set-at-a-time INSERT, UPDATE, and DELETE operators.

Physical data independence 

Changes to physical level (how data is stored, whether in arrays or linked lists etc.) must not require a change to an application based on structure.

Logical data independence 

Changes to logical level (tables, rows, columns and so on) must not require a change to an application based on structure. Logical data independence is more difficult to achieve than physical data independence.

Integrity independence 

Integrity constraints must be specified separately from application programs and stored in a catalog.

Distribution independence 

Existing applications should continue to operate successfully

(a) When a distributed version of DBMS is first introduced.

(b) When existing distributed data is redistributed around system.

The non-subversion rule 

If system provides a low-level (record-at-a-time) interface, then that Interface cannot be used to subvert the system (e.g.) bypassing a relational security or integrity constraint.