DBMS

Schema change statements are used to make the alteration to the existing database. The schema change statements are defined using the structured query language i.e. SQL. It must be taken care that whatever changes you made to the schema of an existing database must not affect the existing database. In the section ahead, we will discuss more schema change and schema change … [Read more...] about Schema Change in DBMS

The entity relationship model is a diagrammatic representation of a database that helps the user to identify the entities present in the database and the relationship among the entities. The entity-relationship model is popularly used to design databases. The entity-relationship model plays with the three major components that are entity, attributes and relations. In this … [Read more...] about Entity Relationship Model

Entity relationship diagram is the graphical representation associated with the entity relationship model. ER diagram helps in representing the logical structure of the overall database. It represents the relationship between the entity sets stored in the database. The ER diagram illustrate the concepts in a way that is easy for many users to understand how the information … [Read more...] about Entity Relationship Diagram (ERD)

Relational algebra is query language based on the set theory of mathematics. It is procedural as it defines the sequence in which the query must be operated to retrieve the result. Relational algebra has some basic fundamental operators along with some derived operators. In this section, we will discuss the definition of relational algebra. We will study each operator along … [Read more...] about Relational Algebra in DBMS

Transactions in SQL is a set of SQL statements that must be executed all at once or none of them must be executed. Transaction does not allow partial execution. The concept of transaction help in maintaining the integrity of the data in both the case even if there are multiple operations that are interrelated or there are multiple database users that update the database … [Read more...] about Transactions in DBMS