DBMS. Advantage of Data base management systems

DBMS. Advantage of Data base management systems

1. Agri -Informatics Dr. Shailendra Bhalawe Assistant Professor College of Agriculture Balaghat Jawaharlal Nehru Krashi Vishwavidyalaya Jabalpur (M.P.)

2. Database-Management Data : Facts and figures which relay something specific, but which are not organized in any way. or Data  is unprocessed facts and figures without any added interpretation or analysis. "The price of crude oil is $80 per barrel.“ Information : For data to become information, it must be contextualized, categorized, calculated and condensed or Information  is data that has been interpreted so that it has meaning for the user. "The price of crude oil has risen from $70 to $80 per barrel" gives meaning to the data and so is said to be information to someone who tracks oil prices. Knowledge : Knowledge is closely linked to doing and implies know-how and understanding. or Knowledge  is a combination of information, experience and insight that may benefit the individual or the organization. "When crude oil prices go up by $10 per barrel, it's likely that petrol prices will rise by 2p per litre " is knowledge.

3. What is DBMS? DBMS stands for Database Management System , it is a collection of programs for managing data and simultaneously it support different types of users to create, manage, retrieve, update and store information in efficient way.  A DBMS is also defined as DBMS is software that enables to store, modify, manipulate and extract data from a database. OR Database management systems (DBMS) are computerized systems for organizing, storing, retrieving, updating and analyzing large and related data quickly and efficiently to provide useful information for decision-making for specific purposes and situations.

4. DBMS are software systems used to store, retrieve and run queries on data. A DBMS serve as an interface between an end-user and a data base, allowing users to create, read update and delete data in the database. A computerized data-keeping system. Software tool used to perform various types of operations on Data in database. DBMS provides an interface to perform various operations like database creation, storing data in it updating data, creating a table in the database and a lot more. It provides protection and security to the database. In the case of multiple users, it also maintains data consistency. 1960- Charles Bachman designed first DBMS system .

5. Component of DBMS User: Application programmers, end user, database administrator. Software: Control the storage, management, retrieval of data in data base. Hardware: Input device, output device, network device, storage device. Data: data stored in database, numerical, non numerical or logical data.

6. Advantages of DBMS Controls database redundancy : It can control data redundancy because it stores all the data in one single database file and that recorded data in placed in the database. Data sharing : In DBMS, the authorized users of an organization can share the data among multiple users. Easily maintenance : It can be easily maintainable due to the centralized nature of the database systems. Reduce time : It reduces development time and maintenance need. Backup: It provides backup and recovery subsystems which crate automatic backup of data from hardware and software failures and restores the data if required. Multiple user interface ; It provides different types of user interfaces like graphical user interfaces, application programmer interfaces.

7. Disadvantages of DBMS Cost of Hardware and Software : It requires a high speed of data processor and large memory size to run DBMS software. Size : It occupies a large space of dist and large memory to run them efficiently. Higher impact of failure : Failure is highly impacted the database because in most of the organization, all the data stored in a single database and if the database in damaged due to electric failure or database corruption then the data may be lost forever..

8. Uses/Applications of DBMS:  It is used in wide range in many sectors like Banking Airlines Universities Human Resource Departments Manufacturing and selling Industries Agriculture Insurance, Medial & Health, weather forecast etc .

9. Functions of DBA (Database Administrator) are: Schema definition : Creation of the original database schema is accomplished by writing a set of definitions which are translated by the DDL compiler to a set of tables that are permanently stored in the data dictionary. Storage Structure and access method definition : The creation of appropriate storage structure and access method is accomplished by writing a set of definitions which are translated by the data storage and definition language compiler. Schema and Physical organization modification : DBA involves either the modification of the database schema or the description of the physical storage organization. These changes, although relatively rare, are accomplished by writing a set of definitions which are used by either the DDL compiler or the data storage and definition language compiler to generate modification to the appropriate internal system tables (for example the data dictionary).

10. Granting of authorization for data access : DBA allows the granting of different types of authorisation for data access to the various users of the database. Integrity constraint specification : The DBA specifies the constraints. These constraints are kept in a special system structure, the data dictionary that is consulted by the database manager prior to any data manipulation. Data Dictionary is one of the valuable tools that the DBA uses to carry out data administration.

11. Database Model The structure of the underlying database is called the data model. This structure consists of a collection of conceptual tools for describing data, data relationships, data semantics, and consistency constraints. The various data models falls into three different groups: object-based logical models, record based logical models, and physical models. 1.Logical Data Model 2. Physical data models

12. Logical Data Model A database model is a type of data model that determines the logical structure of a database and fundamentally determines in which manner data can be stored, organized and manipulated. The most popular example of a database model is the relational model. 1. Object-based logical models Object based logical models are used in describing data at the logical and view levels. They are characterized by the fact that they provide fairly flexible structuring capabilities and allow data constraints to be specified explicitly. There are many different models and they are follows: The entity relationship model The object oriented model

13. 2. Record-based logical model Record based logical models are used in describing data at the logical and view levels. In contrast to object-based data models, they are used both to specify the overall logical structure of the database and to provide higher-level description of the implementation. Record-based models are so named because the database is structured fixed format records of several types. Each record type defines a fixed number of fields, or attributes, and each field is usually of a fixed length. The three most widely accepted record-based data models are the Relational Model, Network Model Hierarchical Models.

14. 2. Physical data models Physical data models are used to describe data at the lowest level. In contrast to logical data models, there are a few physical data models in use. Two of the widely known ones are the unifying model and the frame-memory model. Unifying Frame Memory

15. SQL (structured Query Language) SQL is a standard language for storing, manipulating and retrieving data in databases. Structured Query language (SQL)  pronounced as "S-Q-L" or sometimes as "See- Quel "is actually the standard language for dealing with Relational Databases. SQL programming can be effectively used to insert, search, update, and delete database records.

16. 1. DDL is short name of Data Definition Language, which deals with database schemas and descriptions, of how the data should reside in the database. CREATE - to create a database and its objects like (table, index, views, store procedure, function, and triggers) ALTER - alters the structure of the existing database DROP - delete objects from the database TRUNCATE - remove all records from a table, including all spaces allocated for the records are removed COMMENT - add comments to the data dictionary RENAME - rename an object

17. 2. DML is short name of Data Manipulation Language which deals with data manipulation and includes most common SQL statements such SELECT, INSERT, UPDATE, DELETE, etc., and it is used to store, modify, retrieve, delete and update data in a database. INSERT - insert data into a table UPDATE - updates existing data within a table DELETE - Delete all records from a database table 3. DCL is short name of Data Control Language which includes commands such as GRANT and mostly concerned with rights, permissions and other controls of the database system. GRANT - allow users access privileges to the database REVOKE - withdraw users access privileges given by using the GRANT command

18. 4. TCL is short name of Transaction Control Language which deals with a transaction within a database. COMMIT - commits a Transaction ROLLBACK - rollback a transaction in case of any error occurs SAVEPOINT - to rollback the transaction making points within groups SET TRANSACTION - specify characteristics of the transaction

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