Found 62 Articles for RDBMS

Basics of Functional Dependencies and Normalization for Relational Databases

Raunak Jain
Updated on 10-Jan-2023 18:03:42
Introduction Functional dependencies and normalization are important concepts in relational database design. A functional dependency occurs when the value of one attribute determines the value of another attribute. Normalization is the process of organizing a database in a way that reduces redundancy and dependency. It is a crucial step in designing an efficient and effective database structure. What are functional dependencies? Functional dependencies are relationships between attributes in a database. They describe how one attribute is dependent on another attribute. For example, consider a database of employee records. The employee's ID number might be functionally dependent on their name because ... Read More

Difference between NoSQL and RDBMS

Pradeep Kumar
Updated on 22-Jul-2022 07:42:35
Most SQL databases are relational. Relational Databases are tabular and have a pre-determined schema that organizes the data logically. Database management solutions have evolved from the classic relational paradigm to the more flexible and scalable NoSQL approach.Some say NoSQL stands for "non-SQL, " but many refer to it as SQL. NoSQL is a non-relational database management system for certain data models. These data models don't need a schema and are scalable. It offers a system-supported alternative to relational databases' tabular format for storing and retrieving data. NoSQL databases don't require a certain schema. You can store data without worrying about ... Read More

Difference between Primary key and Foreign key in Database

Kiran Kumar Panigrahi
Updated on 11-Jan-2023 15:42:42
In a relational database, keys are the most important elements to maintain the relationship between two tables or to uniquely identify the data from a table. Primary key is used to identify data uniquely therefore two rows can't have the same primary key. It can't be null. On the other hand, foreign key is used to maintain relationship between two tables. The primary key of a table acts as the foreign key in another table. The Foreign key in a table helps enforce Referential Integrity constraint. Read this tutorial to find out more about Primary and Foreign keys and how ... Read More

E.F. Codd’s 12 Rules for RDBMS

karthikeya Boyini
Updated on 14-Jul-2020 08:47:00
Database Management System or DBMS essentially consists of a comprehensive set of application programs that can be leveraged to access, manage and update the data, provided the data is interrelated and profoundly persistent. Just like any management system, the goal of a DBMS is to provide an efficient and convenient environment in which it becomes easy to retrieve and store the information into the database. It goes without mentioning that databases are used to store and manage large amounts of information.To achieve this, the following are the absolute must-haves:Data Modeling − It is all about defining the structures for information ... Read More

What is NoSQL and is it the next big trend in databases?

Sharon Christine
Updated on 16-Jan-2020 11:13:44
What is NoSQL?As per the official Wiki definition: “A NoSQL (originally referring to “non SQL” or “non relational”) database provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relation databases (RDBMS). It encompasses a wide variety of different database technologies that were developed in response to a rise in the volume of data stored about users, objects and products, the frequency in which this data is accessed, and performance and processing needs. Generally, NoSQL databases are structured in a key-value pair, graph database, document-oriented or column-oriented structure.Over decades ... Read More

Difference between DBMS and RDBMS

Kiran Kumar Panigrahi
Updated on 11-Jan-2023 14:50:19
A DBMS (Database Management System) is a software that is used to manage a database. It is used to create, update, delete and maintain a database and it provides controlled access to data. An RDBMS (Relational Database Management System) is a type of DBMS that is based on the relational model of data. It can be regarded as an enhanced version of DBMS. Read this tutorial to find out more about DBMS and RDBMS and how they are different from each other. What is a DBMS? DBMS stands for Database Management System. A DBMS stores data in the form of ... Read More

What is Data Dictionary

David Meador
Updated on 19-Jun-2020 14:01:22
A data dictionary contains metadata i.e data about the database. The data dictionary is very important as it contains information such as what is in the database, who is allowed to access it, where is the database physically stored etc. The users of the database normally don't interact with the data dictionary, it is only handled by the database administrators.The data dictionary in general contains information about the following −Names of all the database tables and their schemas.Details about all the tables in the database, such as their owners, their security constraints, when they were created etc.Physical information about the ... Read More

Relational Set Operators in DBMS

David Meador
Updated on 19-Jun-2020 14:00:35
DBMS supports relational set operators as well. The major relational set operators are union, intersection and set difference. All of these can be implemented in DBMS using different queries.The relational set operators in detail using given example are as follows as follows −Student_NumberStudent_NameStudent_Marks1John952Mary803Damon57Student_NumberStudent_NameStudent_Marks2Mary503Damon986Matt45UnionUnion combines two different results obtained by a query into a single result in the form of a table. However, the results should be similar if union is to be applied on them. Union removes all duplicates, if any from the data and only displays distinct values. If duplicate values are required in the resultant data, then UNION ... Read More

Various Types of Keys in DBMS

David Meador
Updated on 30-Dec-2020 16:08:21
The different types of keys in DBMS are −Candidate Key - The candidate keys in a table are defined as the set of keys that is minimal and can uniquely identify any data row in the table.Primary Key - The primary key is selected from one of the candidate keys and becomes the identifying key of a table. It can uniquely identify any data row of the table.Super Key - Super Key is the superset of primary key. The super key contains a set of attributes, including the primary key, which can uniquely identify any data row in the table.Composite Key -  If ... Read More

Data Independence in DBMS

David Meador
Updated on 20-Jun-2020 07:21:17
A database contains a large amount of data. Not all of that data is user data, some of it can be metadata etc. So, it is very important that a database has data independence.Data independence basically means that if data is changed at a level, it does not impact the data view at the higher levels.Hence, the data at the higher levels should be independent of the data modification in the lower levels. There is two types of data independence. These are −Logical Data IndependenceLogical data is independent from how data is actually stored on the disk. So logical data independence ... Read More
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