Transaction Control language is a language that manages transactions within the database.It is used to execute the changes made by the DML statements.TCL CommandsTransaction Control Language (TCL) Commands are:Commit − It is used to save the transactions in the database.Rollback − It is used to restore the database to that ... Read More

Data definition language (DDL) is a language that allows the user to define the data and their relationship to other types of data.Data Definition language statements work with the structure of the database table.Various data types used in defining columns in a database tableIntegrity and value constraintsViewing, modifying and removing ... Read More

Let’s see the procedure to access database users in DBMS step by step.Step 1 − The request from the user is passed to the DBMS user interface, where oracle engine locates the files for the given relation.The relation is nothing but − table schemaLinking between the recordsStep 2 − The ... Read More

The three-schema architecture divides the database into three-level used to create a separation between the physical database and the user application. In simple terms, this architecture hides the details of physical storage from the user.The database administrator (DBA) responsible is to change the structure of database storage without affecting the ... Read More

The network model was created to represent complex data relationships more effectively when compared to hierarchical models, to improve database performance and standards.It has entities which are organized in a graphical representation and some entities are accessed through several paths. A User perceives the network model as a collection of ... Read More

It is a collection of concepts that can be used to describe the structure of a database. The structure of the database means data types, relationships and constraints that should hold the data nothing but it provides the necessary means to achieve the abstraction.A Model is basically a conceptualization between ... Read More

Normalization is the process of organizing the data in a database. It helps in removing the duplicate values in the database. Normalization divides the large table into smaller tables and links them using relationships.The normal form is used to reduce redundancy from the database table. Normalization is the name given ... Read More

A trigger is a procedure which is automatically invoked by the DBMS in response to changes to the database, and is specified by the database administrator (DBA). A database with a set of associated triggers is generally called an active database.Parts of triggerA triggers description contains three parts, which are ... Read More

In the 2NF, relation must be in 1NF. In the second normal form, all the non-key attributes are fully functional dependent on the primary key. Or a relation is in 2NF, when it is in 1NF and there is no partial dependency.ExampleConsider a relation R (rollno, name, subjectcode, subjectname, duration)RollnoNameSubjectcodeSubjectnameDuration1HariS1C60 ... Read More

A set of functional dependencies (FD) F is said to cover another set of functional dependencies E if every FD in E is also in F closure; that is, if every dependency in E can be inferred from F.Alternatively, we can say E is covered by F. Two sets of ... Read More