LO4 Database Management System

See you again..

In this lesson in class we learned about database. Database means an organized collection of data and Collection of information arranged and presented in alphabetical order. It also mechanism for storing, managing and retrieving information. There are three functions of database to store, organize, and to control data.

Besides that, in database component I learned about data item and schema the definition data item is field in data processing and it is a piece of information and schema is like  describes the organization of data and relationships within the database. The schema consists of definitions of the various types of record in the database, the data-items they contain and the sets into which they are grouped.

The architecture of a modern database consists of actual database (contents), hardware to process and store the data, software to manipulate the contents and also People to administer the access, control and modification of data.

Database Management System= a software package for manipulating databases= database program

Here we can see database management system

·         dBASE

·         PostgreSQL

·         Microsoft Access

·         SQL Server

·         MySQL

·         FileMaker

·         Oracle

·         RDBMS                                                                       

·         Clipper

Here also we can see three types of database languages

*        DDL (Data definition language)

*         DML (Data manipulation language)

*         Structured Query Language (SQL)

Component which is important in database is field, record, table, key field, relational database, objects. Table in database called as entity. It represent a particular object in the real world ( a person, a place, or an event) and entities can be thought of as nouns. Normally represented in tables. schema and relationship describes an relationship among entities. A relationship works by matching data in key columns. These relationship can be shown in the form of diagram and entity Relationship Diagram  (ERD). Data models use three types of relationships and example 3 forms of ERD are

-          One to One (1:1)In a one-to-one relationship, each row in one database table is linked to 1 and only 1 other row in another table

-           One to many (1:M)In a one-to-many relationship, each row in the related to table can be related to many rows in the relating table.

-           Many to many (M:N)One or more rows in a table can be related to many rows in another table.

The user for database management system is and user, application programmers, and database administrator. Data model need structure, characteristic, description and organization database. Four types database is Hierarchical database, Network database, Relational database and Object-relational database. There are three types of database which is individual (primarily used by one person), company/shared (stored on a mainframe by a computer professional)and distributed (stored in not just one location but in several locations).