A database management system (DBMS) is essentially a computerised data management system. Users of the system can perform different types of operations on such systems in order to manipulate the data in the database and manage the database structure itself. Database management systems (DBMS) are categorised according to data structure or type.
Computer users can categorise database management systems according to the database models they support. Initially, these model data are rows and columns of a set of tables, most of which use SQL to write data and execute queries. Later, non-relational databases, collectively known as NoSQL, became popular because they used different query languages.
The DBMS weight is about 8 to 10 marks at GATE, which is relatively more than many other topics. We have provided a DBMS GATE CSE weight analysis of GATE previous years in the table below. If you can score well in the DBMS, it will help you achieve a better rank in the GATE exam.
|2021||Transaction and Concurrency Control, Normalization, SQL, Normal Forms|
|2020||Transaction and Concurrency Control, ER model, SQL, Database Design|
|2019||Transactions and Concurrency, File System, Normalization, Relational Algebra|
|2018||Natural Join, Left Outer Join, Normal Forms, ER model, Mappings, Relational Algebra|
|2017||Functional Dependencies, SQL Query, Transactions, Tuple Query, Transaction, Relational Algebra, Timestamp|
|2016||Normalization; Transaction & Concurrency Control|
|2015||E-R Diagram, SQL, Relational Algebra & Relational Calculus, Transaction and Concurrency Control, File Structure, Functional Dependency & Normalization|
Transaction in DBMS
A transaction is a group of tasks in DBMS where a single task refers to a minimum processing unit, and we cannot divide it further. Transaction in DBMS is a set of logically related operations. For example, suppose any worker transfers an amount from X’s account to Y’s. This given small and simple transaction can be easily achieved through various low-level tasks.
These various low-level transactions in DBMS must maintain ACID – A (Atomicity), C (Consistency), I (Isolation) and D (Durability). One must maintain ACID so as to ensure completeness, accuracy, and integrity of data.
It is an important topic for the GATE exam. Also, as you can see in the table above, it has been included in the question papers in recent years.
Normal Forms in DBMS
The process of organising data or pieces of information in a database is known as normalization. This process helps us eliminate the repetition or data redundancy from a set of relations or a single relation. It also helps us eliminate several undesirable characteristics, such as Update, Insertion, and Deleting of Anomalies. Normalization in DBMS also helps avoid all the undesirable attributes in a database, such as anomalies with Deletion, Update, and Insertion.
Types of normal forms in DBMS
There are four major forms: INF, 2NF, 3NF, and BCNF.
|1NF||A relation is in 1NF when it consists of an atomic value.|
|2NF||A relation is in 2NF when it is already in 1NF, but all the non-key attributes fully and functionally depend on their primary keys.|
|3NF||A relation is in 3NF when it is already in 2NF, but it does not consist of any transition dependencies.|
|4NF||A relation is in 4NF when it is in BCNF or Boyce-Codd Normal Form, but it does not have any multi-valued dependencies.|
|5NF||A relation is in the 5NF when it is already in 4NF, but it does not consist of the join dependencies.|
Normalization is another important topic included in the GATE DBMS topic. There are questions from normalization almost every year. Hence, the candidates are suggested to cover every bit possible of the syllabus to achieve a good rank.