To ensure the integrity and consistency of data during a transaction (A transaction is a unit of program that updates various data items, read more… [Read More]

In DBMS you may hear cardinality term at two different places and it has two different meanings as well. In Context of Data Models: In… [Read More]

RDBMS stands for relational database management system. A relational model can be represented as a table of rows and columns. A relational database has following… [Read More]

The attributes of a table is said to be dependent on each other when an attribute of a table uniquely identifies another attribute of the… [Read More]

Multivalued dependency occurs when there are more than one independent multivalued attributes in a table. For example: Consider a bike manufacture company, which produces two… [Read More]

A functional dependency is said to be transitive if it is indirectly formed by two functional dependencies. For e.g. X -> Z is a transitive… [Read More]

If a functional dependency X->Y holds true where Y is not a subset of X then this dependency is called non trivial Functional dependency. For… [Read More]

The dependency of an attribute on a set of attributes is known as trivial functional dependency if the set of attributes includes that attribute. Symbolically:… [Read More]

Database languages are used to read, update and store data in a database. There are several such languages that can be used for this purpose;… [Read More]

Data Model is a logical structure of Database. It describes the design of database to reflect entities, attributes, relationship among data, constrains etc. Types of… [Read More]

In hierarchical model, data is organized into a tree like structure with each record is having one parent record and many children. The main drawback… [Read More]

In relational model, the data and relationships are represented by collection of inter-related tables. Each table is a group of column and rows, where column… [Read More]

An Entity–relationship model (ER model) describes the structure of a database with the help of a diagram, which is known as Entity Relationship Diagram (ER… [Read More]

Key plays an important role in relational database; it is used for identifying unique rows from table. It also establishes relationship among tables. Types of… [Read More]

As we have seen in the candidate key guide that a table can have multiple candidate keys. Among these candidate keys, only one key gets… [Read More]