Semantic Data Control

Semantic data control typically includes view management, security control, and semantic integrity control. views, security constraints, and semantic integrity constraints can be defined as rules that the system automatically enforces. Views enable full logical data independence. All views can be queried as base relations, but not all view can be updated as such – Updates through […] Read more»

Distributed Database Design

Design problem • Design strategies(top-down, bottom-up) • Fragmentation (horizontal and vertical) • Allocation and replication of fragments, optimality, heuristics   Top-down approach – Designing systems from scratch – Homogeneous systems Bottom-up approach – The databases already exist at a number of sites – The databases should be connected to solve common tasks   Distribution design […] Read more»

What is Distributed Database System

A distributed database is a collection of databases which are distributed over different computers of a computer network. Advantages: Local Autonomy: permits setting and enforcing local policies regarding the use of local data (suitable for organization that are inherently decentralized). Improved Performance: The regularly used data is proximate to the users and given the parallelism […] Read more»

Distributed Database Architecture

Architecture: The architecture of a system defines its structure: – the components of the system are identified; – the function of each component is specified; – the interrelationships and interactions among the components are defined.   Motivation for standardization of DDBMS architecture: a. Homogeneous DDBMS b. Heterogeneous DDBMS   Reference Model: A conceptual framework whose […] Read more»