Introduction

• Declarative Data

• Procedural Data

-when both declarative & procedural data are stored, the database is sometimes called a knowledge base

Data Subsystem

1) data about designs(e.g., manufacturing designs)

2) images, graphics, audio, & video

– object-oriented

– data warehouses– data mining

Access Controls

• Discretionary access control

• Mandatory access control

Discretionary Access Controls

• Create a schema;

• Create, modify, or delete views associated with the schema;

• Create, modify, or delete relations associated with the schema;

• Create, modify, or delete tuples in relations associated with the schema; &

• retrieve data from tuples in relations associated with the schema.

Discretionary Access controls cont.

1. Name-dependent restrictions

2. Content-dependent restrictions

3. Context- dependent restrictions

4. History-dependent restrictions

1) Name-dependent restrictions

2) Content-dependent restrictions

3) Context-dependent restrictions

A view grants privileges to another user who in turn grants these privileges to another user, the privileges are said to Propagate

•Horizontal Propagation Control

•Vertical propagation Control

Mandatory Access Controls

• Resources are assigned a classification level & users are assigned a clearance level.

– Filtering– polyinstantiation

Integrity Controls

• Integrity constraints: to maintain the accuracy, completeness, & uniqueness of instances of the constructs used within the conceptual modelling or data modelling approach used to represent the real-world phenomena

ER Model Integrity Constrains

Uniqueness Each instance of an entity must be uniqueMaximum cardinality Specifies the maximum number of instancesEntity identifier Specifies the minimum number of instancesValue type of identifier specifies the allowed value typesfor the attributesValue set of identifier Specifies the allowed set of values for the attributes

Integrity Constrain t Explanation