Database Management System
Database Management system(DBMS)
The collection of inter-related data which is used to retrieve, insert and delete the data efficiently is known as database. It is also used to organize the data in the poper manner such as in the form of table, schema, views, and reports, etc.
A DBMS is a set of programs that manages the database files. The DBMS acts as an interface between the application program and the data in the database. Example are: Ms Acess, Oracle and MySQL etc.
DBMS allows:
1. Data definition
2. Data updation
3. Data retrival
4. Data administration
Characterstics of DBMS
• DBMS reduce the complex relationship between data.
• DBMS provide security of data.
• DBMS view the database from different viewpoint.
• DBMS store and manage the information.
• DBMS contains automatic backup and recovery procedures.
Advantages of DBMS
• DBMS reduce time.
• DBMS provide multiple user interface.
• DBMS control data redundancy.
• DBMS provides backup and recovery.
• DBMS can be easily maintained.
Disadvantages of DBMS
• Cost of hardware and software may be high.
• DBMS occupies large space.
• DBMS increase complexity.
Concept of MS Access
MS Access is a powerful multi-user RDBMS ( Relational Database Management system) developed by Microsoft Corporation and can be used to store and manipulate large amounts of information and perform repetitve tasks. MS Access database file contains several different types of database objects:
• Saved queries for organizing data.
• Forms for interacting with the data on the screen.
• Reports for printing results.
MS Access contains four major areas:
• Tables store data in the database.
• Queries ask questions about information stored in the tables. It is used to access the required data from the database.
• Forms allow viewing and inserting data into the tables.
• Reports allow printing data based on queries and tables.
Data Types in MS Access
MS Access supports different types of data, each with a specific purpose. Here are some of the most common data types you will find used in a typical MS Access database.
| Types of Data | Description | Size |
|---|---|---|
| Short Text | Text or combinations of text and numbers. | Up to 255 characters. |
| Long Text | Lengthy text or combinations of text and numbers. | Up to 63,999 characters. |
| Number | Numeric data used in mathematical calculations. | 1,2,4 or 8 bytes ( 16 bytes if set to Replication ID). |
| Date/Time | Date and time values for the years 100 through 9999. | 8 bytes |
| Currency | Currency values and numeric data used in mathematical calculations involving data with one to four decimal places. | 8 bytes. |
| AutoNumber | A unique sequential ( incremented by 1 ) number or random number assigned by Microsoft Access whenever a new record is added to a table. | 4 bytes ( 16 bytes if set to Replication ID). |
| Yes/No | Yes and No values and fields that contain only one of two values ( Yes/No, True/False, or On/Off). | 1 bit. |