Relational data model in DBMS
The relational data model is a way of organizing data in a database as a series of tables. It is based on the concept of a relation, which is a set of rows and columns that represents a single entity.
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| Relational data model in DBMS SKILLS ARENA |
In a relational database, each table contains a set of records, or rows, that represent individual entities. Each record has a set of fields, or columns, that contain the data for that entity. The fields in each record have a specific data type, such as integer, text, or date, that specifies the type of data that they can store.
Domain: It contains a set of atomic values that an attribute can take.
Attribute: It contains the name of a column in a particular table. Each attribute Ai must have a domain, dom(Ai)
Relational instance: In the relational database system, the relational instance is represented by a finite set of tuples. Relation instances do not have duplicate tuples.
Relational schema: A relational schema contains the name of the relation and name of all columns or attributes.
Relational key: In the relational key, each row has one or more attributes. It can identify the row in the relation uniquely.
The relational model is based on the idea of a primary key, which is a field that uniquely identifies each record in a table. The primary key is used to relate records in different tables to one another through the use of foreign keys. A foreign key is a field in one table that references the primary key of another table.
Properties of relational model:
*) Name of the relation is distinct from all other relations.
*) Each relation cell contains exactly one atomic (single) value
*) Each attribute contains a distinct name
*) Attribute domain has no significance
*) tuple has no duplicate value
*) Order of tuple can have a different sequence
The relational model is used in many popular database management systems, such as MySQL, Oracle, and Microsoft SQL Server. It is a flexible and powerful model that is well-suited for a wide range of applications, from small to large-scale systems.
One of the key advantages of the relational model is that it allows for the manipulation of data using Structured Query Language (SQL), which is a standardized language for accessing and manipulating databases. SQL provides a powerful set of tools for creating, modifying, and querying relational databases, making it a popular choice for many developers.
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Created by-- HARSH CHAUHAN
