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Constraints are a very important feature in a relational model. In fact, the relational model supports the well-defined theory of constraints on attributes or tables. Constraints are useful because they…

The entity relationship (ER) data model has existed for over 35 years. It is well suited to data modelling for use with databases because it is fairly abstract and is easy to…

The relational data model was introduced by C. F. Codd in 1970. Currently, it is the most widely used data model. The relational model has provided the basis for: Research on…

Data modelling is the first step in the process of database design. This step is sometimes considered to be a high-level and abstract design phase, also referred to as conceptual design.…

Database management systems can be classified based on several criteria, such as the data model, user numbers and database distribution, all described below. Classification Based on Data Model The most popular…

High-level Conceptual Data Models High-level conceptual data models provide concepts for presenting data in ways that are close to the way people perceive data. A typical example is the entity…

Managing information means taking care of it so that it works for us and is useful for the tasks we perform. By using a DBMS, the information we collect and…

What Is a Database? A database is a shared collection of related data used to support the activities of a particular organization. A database can be viewed as a repository…

The way in which computers manage data has come a long way over the last few decades. Today's users take for granted the many benefits found in a database system.…