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

Join operations in SQL integrates two relations from the database to form a new relation. The relations are integrated or merged based on the common columns present in the two relations. In the section ahead, we will be discussing all forms of join in SQL. Types of Join Operations in SQL Natural Join Equi Join Theta Join Semi Join Outer Join Natural … [Read more...] about Join Operations in SQL

Functions in SQL are the executable blocks that are created and stored in the database. The functions can be invoked from the SQL statements whenever required. Though SQL has some inbuilt functions but the developers can write their own user-defined functions. The functions in SQL are similar to the procedures in SQL that we have discussed earlier. But both of them share … [Read more...] about Functions in SQL

Triggers in SQL are the programs that are executed automatically when a certain condition is met. The trigger can even be used to maintain the integrity of data. The triggers are created and stored in the database and then it is the responsibility of the database system to get the trigger executed whenever a certain condition is met. In this section ahead we will discuss the … [Read more...] about Triggers in SQL

Procedures in SQL are the small subprograms or executable named blocks that can be created and saved in the database. These procedures can be invoked and executed whenever required. It is similar to functions or methods in other programming languages such as C, C++ and Java, etc. In the section ahead, we will discuss the procedure in-depth such as how it is defined, how it … [Read more...] about Procedures in SQL

Views are virtual tables whose tuples or records do not physically exist in the database. Instead, the tuples of this virtual relation or virtual table are computed spontaneously when the user executes the query associated with the view. The database stores the query associated with the view so that the user does not have to write the query again and again. In the section … [Read more...] about Views in SQL