The World Of Database Systems

Parallel Computing

The ability to store huge amounts of data is important, but it would be of little use if we could not access large amounts of that data quickly. Thus, very huge databases also require speed enhancers.

Client-Server and Multi-Tier Architectures

Numerous different types of present software use a client-server architecture, in which requests by one process (the client) are sent to another process (the server) for implementation

Multimedia Data

One of the important trends in database systems is the addition of multimedia data. By multimedia" we mean information that represents a signal of some sort. Common types of multimedia data include video, audio, radar signals, satellite images, and documents or pictures in different encodings.

Information Integration

As information becomes ever more important in our work and play, we find that existing information resources are being used in many new ways. For instance, consider a company that wants to provide on-line catalogs for all its products

Overview of a Database Management System

In following Figure we see an outline of a complete DBMS. Single boxes represent system components, while double boxes represent in-memory data structures.

Data-Definition Language Commands

The second type of command is the simpler to process, and we show its trail beginning at the upper right side of Figure. For example, the database administrator, or DBA, for a university registrar's database

Overview of Query Processing

The great majority of connections with the DBMS follow the path on the left side of following figure. A user or an application program starts some action that does not affect the diagram of the database

Storage and Buffer Management

The data of a database generally exists in secondary storage; in today's computer systems secondary storage" generally means magnetic disk. However, to carry out any useful operation on data,

Transaction Processing

It is normal to group one or more database operations into a transaction, which is a unit of work that must be carried out atomically and in obvious separation from other transactions. In addition

The Query Processor

The portion of the DBMS that most affects the performance that the user sees is the query processor. In following figure the query processor is

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