Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
In this post, we will understand the difference between 3NF and BCNF.3NFThere shouldn’t be any transitive dependency.There shouldn’t be any non-prime attribute that depends transitively on a candidate key.It is not as strong as BCNF.It has high redundancy.The functional dependencies are already present in INF and 2NF.It is easy to achieve.It can be used to achieve lossless decomposition.BCNFFor any relation A->B, ‘A’ should be a super key of that specific relation.It is stronger than 3NF.The functional dependencies are present in 1NF, 2NF and 3NF.It has low redundancy in comparison to 3NF.The functional dependencies may or may not be preserved.It is ... Read More
In this post, we will understand the difference between MySQL and PostgreSQL.MySQLIt is a relational database management system.It is the product developed by Oracle Corporation.It is supported by Windows, Mac OS X, Linux, BSD, UNIX, z/OS, Symbian, AmigaOS.It can’t be extended.In this system, the phpMyAdmin tool gives the GUI.Mysqldump and XtraBackup provide backup in MySQL.It provides temporary table.It doesn’t provide a materialized view.It doesn’t provide Data Domain Object to the system.PostgreSQLIt is an object-relational database management system.It was developed by the Global Development Group.It is supported by Windows, Mac OS X, Linux and BSD but not by UNIX, z/OS, Symbian, ... Read More
In this post, we will understand the difference between WHERE clause and HAVING clause in SQL.WHERE ClauseIt is used to filter the records from the table based on a specific condition.It can be used without the ‘GROUP BY’ clause.It can be used with row operations.It can’t contain the aggregate functions.It can be used with the ‘SELECT’, ‘UPDATE’, and ‘DELETE’ statements.It is used before the ‘GROUP BY’ clause if required.It is used with a single row function such as ‘UPPER’, ‘LOWER’.HAVING ClauseIt is used to filter out records from the groups based on a specific condition.It can’t be used without the ... Read More
In this post, we will understand the difference between T-SQL and PL-SQL.T-SQLIt is a Microsoft product.It is known as Transact Structure Query language.It gives a high degree of control to the developers/programmers.It works its best, and provides good performance with Microsoft SQL server.It is easy.It is simple to understand.It allows the insertion of multiple rows into a table.This is done with the help of the ‘BULK INSERT’ statement.The ‘SELECT INTO’ statement is used in T-SQLIn this, the ‘NOT EXISTS’ clause can be used with the ‘SELECT’ statements.PL-SQLIt is an Oracle product.It is known as Procedural Language Structural Query Language.It is ... Read More
In this post, we will understand the difference between COMMIT and ROLLBACK in SQL.COMMITIt validates the modifications that are made by the current transaction.Once the COMMIT statement has been executed, the transaction can’t be rolled back using ROLLBACK.It occurs when the transaction is successfully executed.SyntaxCOMMIT;ROLLBACKIt removes the modifications that were made by the current transaction.Once ROLLBACK is executed, the database would reach its previous state.This is the state where the first statement of the transaction would be in execution.ROLLBACK happens when the transaction is aborted in between its execution.SyntaxROLLBACK;
In this post, we will understand the difference between linear regression and logistic regression.Linear RegressionIt helps predict the variable that is continuous, and is a dependent variable.This is done using a given set of independent variables.It extrapolates a line to find the value of dependent variable.Least square methods are used to estimate the accuracy.The best fit line is found, that helps predict the output.It is generally a continuous value.The relation between the dependent variable and independent variable has to be linear.The independent variables may have collinearity between them.It is considered a machine learning problem, i.e an applied statistics problem.Logistic RegressionIt ... Read More
In this post, we will understand the difference between clustered index and non-clustered index.Clustered indexIt is quick.It requires less memory to perform operations.The index is the main data.A table can have one clustered index only.It has inherent ability to store data on the disk.It can store pointers to block not to data.The leaf nodes contain actual data.The clustered key defines the order of data within table.It is a type of index where the table records are physically reordered to match with the index.Non-clustered indexIt is slower.It requires more memory to perform operations.The index is a copy of data.A table can ... Read More
In this post, we will understand the difference between grant and revoke.GrantIt is a DCL command.It grants permissions to users on database objects.It can also be used to assign access rights to users.For every user, the permissions need to be specified.When the access is decentralized, permission granting is easier.Syntax:grant privilege_name on object_name to {user_name | public | role_name}RevokeIt is a DCL command.It removes permissions if they are granted to users on database objects.It takes away/revokes the rights of the users.If access for a user is removed, all specific permissions provided by that user to others will be removed.If decentralized access ... Read More
In this post, we will understand the difference between SQL and T-SQL.SQLIt is a non-procedural language.Relational databases use SQL.It stands for structured query language.It uses query to view and manipulate data.DML and DDL operations are used- Data manipulation language, and data definition language.It is considered as an open-source language.It helps in the manipulation of data and data controlling.Transfer of data happens one by one when SQL is used.T-SQLIt is a Microsoft product.It is known as Transact Structure Query language.It gives a high degree of control to the developers/programmers.It works its best, and provides good performance with Microsoft SQL server.It is ... Read More
In this post, we will understand the difference between backup and recovery.BackupIt refers to storing a copy of the original data in a separate memory location.It is basically a copy of data that is used to restore the original data in case of a data loss/damage.It is the replication of data.It just keeps one extra copy to ensure data is not lost forever.It helps in giving data protection.It makes the process of data recovery hassle free and easy.It is an affordable process.It is used in production environments.Example - SnapManager helps create a backup of data and everything else in the ... Read More