basics of java with oops concept with dbms .Relational algebra consists of various basic operators that help us to fetch and manipulate data from relational tables in the database to perform certain operations on relational data. Basic operators are fundamental operations that include selection (σ), projection (π), union (U), set difference (−), Cartesian product (×), and rename (ρ).and sql based query technique with basics of springboot orm, jpa, hibernate