The key is unique for every lock. Similarly, those attributes which are unique for every entity in a single table, are known as key attributes. Keys are nothing else only the unique attributes associated with every entity. Keys are useful in dbms for various reasons such as data integrity, efficient data retrieval, data consistency, data …
Decomposition means dividing a large and complex table into multiple small and easy tables. This removes redundancy, anomalies, and inconsistency in a database. This is the first stage of normalization. Suppose we have a relational schema R, in which we have attributes as given below: A1, A2, A3…………An So R = {A1, A2, A3…………An} If …
The degree of relationship means the number of entities associated with a relationship in a relational model. Based on the number of entities associated we have the following degree of relationships. Unary Relationship In this only a single entity is associated in a relation. It is mostly used to represent the recursive relationship, which means …
A Database is a very complex mechanism to handle and control a large amount of data. As we all know the overall design of the database is known as database schema which is further divided into three categories as given below: The database or relational schema looks quite simpler and effective from the top but …
A database system is a very huge and complex application. To understand the complete structure of a database we should divide it into small modules. Let’s discuss them one by one in detail. Users Those who interact with the database. On the basis of how they use the database we can divide them into three …
According to tasks performed on the database by different users, we can classify database users in 5 categories as given below: Database Administrator Naive Users Application Programmers Sophisticated Users Specialized Users Let’s discuss each one by one in detail. 1. Database Administrator (Super Users) A single person or a team of members can be a …
Interface means “The way of communication performed in between a user and a Database management system” like query passing. This interface is further divided into four categories on the basis of technology used. Menu based Form based Graphical user interface (GUI) based Natural language based Let’s discuss them one by one in detail. Menu Based …
Programming languages which are used to create and operate database, known as database language like Structured Query language aka SQL etc. Most of database languages are non-procedural, means the language focus on “what to do instead of how to do?” We can further divide database languages in these 4 categories as per the type of …
