Week 7
In every week I was happy because I used to know more about the course and I see that I have improved a lot.
Apply relational database design approach and implement it using Microsoft Access or other DBMS
• Database: A collection of interrelated data stored together with controlled redundancy to serve one or more applications in an optimal way. The data are stored in such a way that they are independent of the programs used by the people for accessing the data.
• Database Management System: a software system for manipulating databases.
Database Management Systems
The DBMS performs the following five primary functions:
• Define, create and organise a database: The DBMS establishes the logical relationships among different data elements in a database and also defines schemas and subschemas using the DDL.
• Input data: It performs the function of entering the data into the database through an input device (like data screen, or voice activated system) with the help of the user.
• Process data: It performs the function of manipulation and processing of the data stored in the database using the DML.
• Maintain data integrity and security: It allows limited access of the database to authorised users to maintain data integrity and security.
• Query database: It provides information to the decision makers that they need to make important decisions. This information is provided by querying the database using SQL
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.
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.
To conclude:
• A database is a collection of data which has been organised so that a computer program can quickly select desired items.
• DBMS is a software tool to manage incoming data, organize it, and provide ways for the data to be modified or extracted by users.
• Example of DBMS is Microsoft Access
No comments:
Post a Comment