1

I was going through some text on operations on relations and relational algebra.

It stated:

Some people use term “RESTRICT” for SELECT – possibly to avoid conflict with SELECT in SQL - both are different.

What is the difference?

Rip Hunter
  • 97
  • 1
  • 11

1 Answers1

0

The RESTRICT operation in Relational Algebra is commonly known as the SELECT operation, but its functionality is different to the SQL SELECT statement.

SQL SELECT is used to retrieve data from a database, making it possible to retrieve either the entire table or according to some specified rules. Syntax: SELECT <field_names_of_table> FROM <table_name>;

The Selection operation in RA chooses the subset of tuples from the relation that satisfies the given condition mentioned in the syntax of selection. Syntax: RESTRICT <relation_name> WHERE <given_condition>

Refer the following link for a description on the Restrict operation in RA: Relational Algebra Introduction

Sachini Ginige
  • 1
  • 2