Relation and Relation schema are the terminologies of SQL and Relation is known as Table and Relation Schema is known as Table definition. In other words, Relation schema defines the meta data elements which represent a particular domain. For example, they define the structures and constraints of data. On the other hand, relation is the predicate for example, Relation schema for a person "relation" can be shown in the following manner:
Person(FirstName, LastName, Age, Gender, Address)
Database Schema: Database schema is a collection of meta-data that describes the relations in a database. A schema can be simply described as the "layout" of a database or the blueprint that outlines the way data is organized into tables. Schema are normally described using Structured Query Language as a series of CREATE statements that may be used to replicate the schema in a new database.
Relation schema: A relation schema can be thought of as the basic information describing
a table or relation. This includes a set of column names, the data types associated
with each column, and the name associated with the entire table.
Relation and Relation schema
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.
Relation schema is a type definition and relation is an instance of that schema