Null values present special problems in relational operations, including arithmetic operations, comparison operations, and set operations .
The natural join operation operates on two relations and produces a relation as the result.
We introduced the natural join operation. SQL provides other forms of the join operation, including the ability to specify an explicit join predicate, and the ability to include in the result tuples that are excluded by natural join. We shall discuss these forms of join in this section.
Sensitivity of data is a measure of the importance assigned to the data by its owner, for the purpose of denoting its need for protection. Some databases contain only sensitive data while other databases may contain no sensitive data at all.
The typical method of enforcing discretionary access control in a database system is based on the granting and revoking of privileges. Let us consider privileges in the context of a relational DBMS.
Conceptual modeling is a very important phase in designing a successful database application. Generally, the term database application refers to a particular database and the associated programs that implement the database queries and updates.
The main Idea for the Sampling Algorithm is to select a small sample , one that fits in main memory of the database of transaction
A database schema, along with primary key and foreign key dependencies, can be depicted by schema diagrams.