Describe the differences in meaning between the terms relation and relation schema?

Answer 1

Relational Schema refers to meta-data elements which are used to describe structures and constraints of data representing a particular domain. Whereas a relation is a property or predicate that ranges over more than one argument Here's some translation from "Relational Algebra" to SQL terminology: * "Relation" = Table. * "Relation Schema" = Table definition. So for example, the "schema" for the Person "relation" is: Person(FirstName, LastName, Age, Gender, Address) Also in relational Algebra, a "tuple" is a table row, and an "attribute" is a table column.
Mathematician define a relation to be subset of cartesian product list of domains.

In daabase relation is a set of entities with similar attributes.

In other way we can consider a relation as a table and it's rows as entities, and table's columns as attributes.Concept of relation corresponds to programming language notion of variable.

relational Schema corresponds to the programming language notion of type definition.

It is the logical design of database.

e.g. for a relation account having attributes account_number, branch_name and balance, relational schema is specified as -

Account_schema= (account_number, branch_name, balance)