DBMS

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

Classification of database management system is based on various parameters such as the kind of data model used to construct the DBMS, the number of users that will be using the database system, the way in which the database is distributed. In the section ahead, we will be discussing all the criteria on which the database system can be classified. Classification of Database … [Read more...] about Classification of Database Management System

Domain relational calculus (DRC) is a formal query language that is 'non-procedural' and 'declarative'. Being a form of relational calculus the domain relation calculus also specifies what information has to be retrieved, not how that information has to be retrieved.  Domain relational calculus is much similar to the tuple relational calculus the only difference is that the … [Read more...] about Domain Relational Calculus