Chapter 4: DATABASE

DATABASE 
This lesson is a very interesting for me. Because in it is important for me to get that knowledge to to apply in my studies. Moreover, it help in my studies and makes me know more about the use of technology in our daily life. The technology now increase very fast and it guide us easily to know the world. It also makes the world smaller and smaller.

Do you know what is database?

Database: is a collection of interrelated data stored together with controlled redundancy to serve one or more applications in an optimal way. One more thing it has three function that we us to store, organize and control DATA.

DATABASE COMPONENTS

• Data item: it is defined as an distinct pieces of information and is explained in the previus section.
• Relationships: I represents a correspondence between various data elements.
• Constraints: These are the predicates that define correct database states.
• Schema: It describes the organisation of data relationships within the database.

This is the Database component

Other than that, I have learnt about Database Management Systems

The DBMS performs the following five primary functions:

1. Define, create and organize a database 
2. Input data
3. Process data
4. Maintain data integrity and security
5. Query database

These are Examples of DBMS

• Microsoft Access
• Oracle
• IBM DB2
• SQL Server
• MySQL

DATABASE SYSTEM

The DBMS software together with the Database is called a database system. It can be defined as an organization of components that define and regulate the collection, storage, management and use of data in a database. It is a system whose overall purpose is to record and maintain information.

Advantages of Database Systems

1. Controlled redundancy
2. Data consistency
3. Sharing of data
4. Improved data integrity
5. Improved security
6. Data access is efficient

TYPES OF DATABASE MODELS

They are four types of database models:

• Hierarchical database
• Network database
• Relational database
• Object-relational database

Hierarchical database

• The hierarchical data model organizes data in a tree structure.
• There is a hierarchy of parent and child data segments.
• This structure implies that a record can have repeating information, generally in the child data segments.
• Hierarchical DBMSs were popular from the late 1960s. with the introduction of IBM's Information Management System (IMS) DBMS, through the 1970s.

Network database

• Resembles hierarchical model.
• Difference child can have multiple parents.
• Some data were more naturally modeled with more than one parent per child.
• The network model permitted the modeling of many to many relationships in data.

We have also learn about the Relational Database which guide us to know more about the database.  It related to the fields that can be use in a number of way (and can be of variable length), provided that they are linked in tables. It is developed based on a database model that provides for logical connections among files (known as tables) by including identifying data from one table in another table. It also tables comprise the fundamental building blocks of any database. Relation, basically a tables with rows and columns.

Database terminology

   Term                  Description

• Field :   A specific piece or data such as a first name, last name, city, state, subject or      birth date.
• Record: A group of related fields that describes a person, place, thing or transaction such as customer, student, location, product, or sale.
• Key field:  A field that contains unique information for each record, such as student ID for a student.
• Table : A collection of records for a single subject such as Students, Products, of Sales.
• Relational database: Multiple tables that are linked together to address a business process such as managing timetable, courses, and students.
• Objects: The parts of Access database that help you view, edit, manage, and analyze the data: tables, queries, forms, reports, macros, and modules.

EXAMPLE: 

DATABASE has many Types of language which we need to use them everyday in our technology that we need for many use. First type is DDL (Data Definition Language). For second type is DML (Data Manipulation Language) and the third is DCL (Data Control Language). All of them have differences function for create language styles.