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In this article:
- What is a database?
- What is a DBMS?
- Types of DBMS
- Features of a DBMS
What is a Database?
Data, when stored in as a collection in an organized manner, is called a database. A database can be understood as a collection of records in a computer. A database is necessarily a form of structured data.
What is a DBMS?
Databases are usually very large in size. They store a huge amount of data that needs to searched, added to and deleted from when the need arises. Due to this property of a database, a software program is required that can manage such operations with ease.
A Database Management System or DBMS is a software program that can manage a database and perform operations on the data contained within it. A Database Management System provides a user-friendly interface to add, delete, modify and search data stored in a database.
Types of DBMS
There are various types of DBMS that have been use in some time or the other. However, there are certain types of DBMS that are standard, i.e, that have been taken as a norm. This section focuses on such DBMS types.
- Navigational DBMS
Navigational DBMSes (or Network DBMSes) were basically created with an aim to provide an industry on which future software could be based. For this purpose, the Navigational DBMS specification was presented in 1971. It was developed by the Database Task Group which was a part of the CODASYL (the organization that led to the making of COBOL programming language). The founder of the task group was Charles Bachman.
Under the navigational approach (or the Codasyl approach), a database was navigated manually. Each record had a ‘link’ to the next record in the database and to other pieces of data. If there were 10 records in the database and the 10th record was required be seen, one had to ‘navigate’ starting at the 1st record right until he reached the 10th one, one after the one. It was for this reason that the name Navigational database was given to such a database. There was no “search” function in them.
- Relational DBMS
The relational DBMS model was based on Edgar Codd’s papers presented on them who worked at IBM in San Jose, California. He proposed this system when hard disks were coming into the market and a need was felt to be able to search any record which the navigational model did not allow. The relational DBMS model was put to use by Eugene Wong and Michael Stonebraker who implemented it in the INGRES project. The INGRES produced products that were used till 1979.
In the relational model, the data is stored in the form of a table that has certain number of rows (tuples) and columns. Two tables were connected or related to each other with the help of a common field present in both of them (called a key). This key helped find data related to the same record in both the tables. Hence, the name for this model was Relational DBMS. An example of this maybe a student record database where one table contains the contact information of the student and another contains his marks. The ‘key’ here is the student’s name or roll number that can show the information about a student from both the tables at once.
- SQL DBMS
SQL DBMS can be seen as a hybrid variety of the Relational DBMS, particularly INGRES. The people who had worked in INGRES made various implementations of it and added support of the Structured Query Language (SQL) to it. This made it easy to search in a database as well as perform other operations. Stonebraker’s own database, PostgreSQL, is the most widely used databases worldwide for many critical applications.
- Object-Oriented DBMS
The above mentioned models led to the development of the Object-oriented DBMS. They allow the user to add records directly into the database without requiring converting it into any format. They are the most modern type of DBMS.
Features of a DBMS
- Modeling Language, which defines the structure of a database (schema)
- Data structures, that organize data to make them easily and efficiently accessible
- A query language, that helps perform operations on the database
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