DBMS: Database concepts

Unit 1

Data

Raw facts

Information

Transformed/processed data that facilitates decision making

Data management

A process that focuses on data collection, storage, and retrieval.

Database

A shared, integrated computer structure that houses a collection of related data.

Contains two types of data: end-user data(raw facts) and metadata

Metadata

Data about data characteristics and relationships

Database management system (DBMS)

the collection of programs that manages the database structure and controls access to the data stored in the database.

Data inconsisency

A condition in which different versions of the same data yield-different (inconsistent) results.

query

a specific request issued to the DBMS for data manipulation

centralized database

A single database located at a single site.

Distributed database

A logically related database that is stored in two or more physically independent sites.

cloud database

A database that is created and maintained using cloud services such as Microsoft Azure or Amazon AWS.

general-purpose database

A database that contains a wide variety of data used in multiple disciplines.

Unstructured data

Data that exists in its original, raw state; that is, in the format in which it was collected.

Structured data

Data that has been formatted to facilitate storage, use, and information generation.

Semistructured data

Data that has already been processed to some extent.

Extensible Markup Language (XML)

A metalanguage used to represent and manipulate data elements.

XML database

supports the storage and management of semistructured XML data.

Problems with File Systems

1. Data redundancy

2. Data inconsistency

3. Lack of data integrity

4. Difficult to access

5. No multi user access

Data redundancy

when the same data is stored unneccessarily at different places.

Data inconsistency

when different and conflicting versions of the same data appear in different places.

Data integrity

Data is accurate and verifiable.

Database system

An organization of components that defines and regulates the collection, storage, management, and use of data in a database environment.

query language

a non-procedural language - one that lets the user specify what must be dont without having to specify how.