Database Management System | Functions of Database Management System
In this article all the information about Database Management System has been given. If you read this article completely, then we are sure that you will understand very well about it.
What is Database Management System ?
A database management system is a software that collects a lot of data, and that data is organized in such a way that it can be easily updated, deleted, accessed, managed.
Meaning that in the database management system data is stored in such a way that it is easy to retrieve, manipulate, and produce the same data.
MySQL
Oracle
dBASE
SQLite
IBM DB2
Microsoft SQL Server
What is the Function of Database Management System ?
Controlling Data Redundancy
In a file-based system, each application program has its own individual file. In this case, duplicate files of the same data are created at multiple locations.
In DBMS, all the data of an organization is integrated into a single database file that means the data is entered at only one place in the database and is not replicated.
Data Consistency
By controlling data redundancy in DBMS, data consistency is achieved.
Meaning that the same type of data is prevented from accumulating again and again in the database, it is called data consistency.
Data Integrity Management
Before inserting any type of value into the DBMS database, it is necessary to satisfy certain conditions.
The user is not allowed to access all the data in the database. Which increases data integrity.
Data Searching
It is very easy to search and retrieve data in DBMS. In old databases, we needed to write a program for each search, but in DBMS we have to write only short queries and users can easily search the information.
Backup and Recovery Management
As we know that a computer is a machine, then there will be some problem with it, whether it is in the hardware part of the computer or in the software part.
In such a situation, there is a danger that the data stored in our computer can be lost.
But DBMS removes this problem from us, meaning that there is a backup of the data stored in the DBMS, so that if the data is lost due to some problem in our computer, then we can recover that data.
Security Management
In DBMS (Database Management System), the administrator has complete control over the data.
In this, the administrator makes sure that to which user the data is to be given, when to give, and how much, and on which part of the database the user is to be allowed to access the data, all these administrator controls, which increases the security of the data.
Types of Database Management System
Below are the types of database management system,
Relational Databases
A relational database is also known as a structured database. In which data is represented in table forms like row and column.
Network Database
A child can have more than one parent in a network database. This type of relationship is called many-to-many. Meaning that the network database is represented as a record.
In which the relationship between one data to another is shown as a link.
Object-Oriented Database
This database stores data as objects. Object-Oriented Database basically follows the principle of Object-Oriented Programming (OOP).
What is E-R Model in Database Management System ?
The full form of the E-R model is the entity-relationship model. This is a graphical approach to database design.
That is, the database is designed by the diagram and visual representation in it.
Entity – An entity is a real-world object in the ER model. The properties of entities are called attributes.
Relationship – The association between entities is called a relationship.
one to one
one to many
many to one
many to many
What is Hierarchical Database ?
The data in the Hierarchical Database is organized like a tree. In this, the relationship between parent and child remains.
In this model, the symbol entity has one parent but many children.
There is only one entity in this which is called root. In a hierarchical database, we can access and update data very fast.
What is Data Abstraction in Database Management System ?
The meaning of data abstraction in DBMS is that the process of extracting data from the many data that we will need is called data abstraction.
Meaning that a lot of data is present in our database in the form of rows and columns, if we need any data then the database shows us the same data which we need data, this is called data abstraction.
Meaning that the process of extracting the needed data out of many data is called data abstraction.
Example: - If we do some search on Google, then Google takes out the list of the same page and puts it in front of us which we need. Like if we search on Google what is Google?
So Google will show pages related to this, the process that happens inside it because Google brings some pages out of many pages, it is all hidden, only the page comes which we need.
Level of data Abstraction
The data structure is very complex, to make it easier, the developers have divided the data into three parts according to the usage, which is called three levels of data abstraction.
Physical level
The physical level is the lowest level of data abstraction. Here all the data of the database is stored.
This level can be accessed only by DBA (Database Administrator) or only System Engineer can access it.
Logical level
The level between the physical and the view level is the logical level.
The logical level is used to see which information or data is present in the database.
It tells about the data types, entities, relationships, etc. of the information stored in the database.
View Level
It is used to collect information from the user and display the information on a need basis.
It is also called the external level. Meaning that when any ordinary user accesses the database, then that user uses this view level only.
Who is Database Users ?
1. Database Administrator (DBA)
The Database Administrator is the one who is very familiar with the database.
The DBA is responsible for any action in the database. It can do any kind of change in the database like delete, update, create.
2. Database Designers
Database designers are those who design the database structure such as Taxi, View, Constraint, etc.
It chooses the right structure to identify and represent the stored data in the database.
3. End-user / Naive Users
These users are those users who do not have much knowledge about the database but use the database application daily.
These users only use the database to complete their tasks.
4. Application Program
These are user programs that write code for application programs in the back end.
Or you can say that this user is the one who writes the program for the database.
5. Casual user / Temporary User
This user is the user who rarely accesses the database. This user sometimes uses the database to get some new information.
6. Sophisticated Users
These users are very familiar with databases and can be user engineers or data analysts.
It develops the database according to its need. This user interacts with the database by writing a query.
7. System Analyst
It analyzes the needs of the end-user and further checks whether all the needs of the end-user are met or not.
Along with this, this user fulfills the feasibility, economic and technical aspects of DBMS.
What is Database Language ?
Data Definition Language (DDL)
DDL stands for Data Definition Language. The language used to design the database is called Data Definition Language (DDL).
The most important DDL statements in SQL are:
1. CREATE:- To create objects in the database.
2. ALTER:- To change the structure of the database.
3. DROP:- To delete the objects from the database.
4. COMMENT:- To add comments to the data dictionary.
5. RENAME:- To rename (change the name) of the object.
7. Truncate: It is used to extract all the records from a table.
Data Manipulation Language (DML)
DML stands for Data Manipulation Language. This language manipulates the data in the database, hence it is called DML (Data Manipulation Language).
An example of DML is,
1. SELECT:- To retrieve data from a database.
2. INSERT:- Inserting data into the table.
3. UPDATE:- To update the existing data in the table.
4. DELETE:- To delete all the records from the table.
5. CALL:- To call java subprogram.
6. LOCK TABLE:- To control the concurrency.
7. Merge: It performs UPSERT operations, which are insert or update operations.
8. Explain Plan: There is a parameter to explain the data.
Data Control Language (DCL)
DCL stands for Data Control Language. The language used to control access to the data stored in the database is called DCL (Data Control Language).
The execution of DCL is transactional. It also has rollback parameters.
DCL Example is,
1. GRANT:- To grant privilege to the users for the database.
2. REVOKE:- REVOKE command is used to take back the privilege given by the GRANT command.
Transaction Control Language (TCL)
TCL stands for Transaction Control Language. TCL is used to drive changes made by DML statements.
TCL example is,
Commit: It is used to save the transaction on the database.
Rollback: This is used to restore the original database since the last commit.
What is Data Dictionary ?
As we know data dictionary means a dictionary that we store in the database. The data dictionary is used to store the information of data like name, table, file, etc.
If we understood in simple language, in DBMS, the data dictionary is a file or group of files that store the metadata of the database. Metadata is that which provides information about the data is called metadata.
Without a data dictionary, DBMS cannot access data from the database.
There are two types of Data Dictionary,
1. Active Data Dictionary
We call an active data dictionary which is automatically updated by the database all the time.
Meaning that if anything is changed in the database then it gets updated automatically.
2. Passive Data Dictionary
We call a passive data dictionary that is not updated automatically by the database.
Meaning it is like an active database but does not have automatic updates.
For example, if we delete or insert something in the database, then it will not be updated automatically.
Either someone will update it or some software will do it.
The database management system is software that collects a lot of data, and that data is organized in such a way that it can be easily updated, deleted, accessed, managed.
Meaning that in the database management system data, the data is stored in such a way that it is easy to retrieve, manipulate, and produce the same data.
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