In this article, we will learn how to secure Mongo DB on Ubuntu 16.04. In previous versions the Mongo DB is vulnerable to automated exploits because, by default, there is no authentication which was allowed to interact with the database, any user can create, read, modify and destroy the database and the contents, this is because of the Mongo DB daemon which can listen to all interfaces as default settings.Enabling Authentication and Adding Admin UserThis issue has been mitigated in the latest versions of Mongo DB after version 3.x releases, however, the authentication is still disabled as default settings, so ... Read More

In this problem, we are given a number n and we have to print all odd numbers from 1 to n and also print the sum of numbers from 1 to n in PL/SQL.PL/SQL is a procedural language extension to SQL. The code is a sequence of instructions that are ground in a block with all related declarations and instructions.Let’s see an example of our problem −Input: 7 Output: odd numbers are: 1, 3, 5, 7 Sum of odd numbers is 16To solve this problem, we will take a number and initialize it to 1 and a sum variable with ... Read More

This article will help you to migrate the database from MySQL to MariaDB as the binary compatibility of MySQL-to-MariaDB in the migration process is very much straightforward.After the Oracle’s acquisition of MySQL, the community has driven an outcome of such movement and developed a new database called MariaDB. MariaDB is the open-source and its compatibility with MySQL. Most of the Linux distributions (RH, CentOS, Fedora) have already started to use the support of MariaDB as a drop-in replacement of MySQL.If we want to migrate the database from MySQL to MariaDB then this article will help.Preparing a MySQL Database and TablesWe ... Read More

MongoDB is a cross-platform, document oriented database that provides, high performance, high availability, and easy scalability. MongoDB works on concept of collection and document. The official Ubuntu 16.04 MongoDB packages have not yet been published by the MongoDB maintainers. This article explains about “How to install Mongo DB on Ubuntu and start the MongoDB service on boot”Adding the MongoDB RepositoryMongoDB is generally included in a Ubuntu package repositories. However, a legitimate MongoDB repository affords the most upto date version change in an endorsed manner.To carry out this process, we first must import the key for the legitimate MongoDB repository using ... Read More

In this article, we will learn how to create a RAID 5 Array configuration using the ‘mdadm’ utility.The ‘mdadm’ is a utility which is used to create and manage storage arrays on Linux with RAID capability where the administrators are having great flexibility in managing the individual storages devices and creating the logical storage with a high performance and redundancy.RAID 5 Array is a type where we implement by striping the data across the total available devices. Every component of the each stripe is calculated by parity block. If any device fails the parity block, it will use the remaining ... Read More

In this article, we will learn how to create a RAID 0 Array configuration using the ‘mdadm’ utility.The ‘mdadm’ is a utility which is used to create and manage storage arrays on Linux with RAID capability where the administrators are having a great flexibility in managing the individual storage devices and creating the logical storage with a high performance and redundancy.RAID 0 array will work by dividing the data into small chunks and strips that data across the available storage disks, which means that each and every storage disk will contain a portion of data and when retrieving the data ... Read More

Stored Procedures Stored Procedures is a group of pre-compiled SQL statements that is stored in a database and can be reused anytime. It allows you to do many things in one command. So doing several activities in a database will be easier and quicker than before. A stored procedure can be called from SQL commands as well as applications like Python, Java, or PHP. Syntax Following is the syntax to create a stored procedure − CREATE PROCEDURE procedure_name AS BEGIN -- SQL statements END; Example Let us create a stored procedure where it ... Read More

SQL query is used to fetch data from the database. In some of the scenario you may need some perquisite data to call subsequent SQL query to fetch data from a table so instead of writing two seperate query we can write SQL query within the query. Therefore subQuery is a way to combine or join them in single query. Subqurey can have two types −Correlated subquery - In correlated subquery, inner query is dependent on the outer query. Outer query needs to be executed before inner queryNon-Correlated subquery - In non-correlated query inner query does not dependent on the outer ... Read More

Oracle golden gate and oracle active data guard is the data replication technologies. They both are used for data replication but with different strategy. As per the oracle docs −Oracle Active Data Guard provides the best data protection and availability for Oracle Database in the simplest most economical manner by maintaining an exact physical replica of the production copy at a remote location that is open read-only while replication is active. GoldenGate is an advanced logical replication product that supports multi-master replication, hub and spoke deployment and data transformation, providing customers very flexible options to address the complete range of replication requirements. ... Read More

Logical standby and physical standby database in two different types of standby database. In case of any failure of primary database Oracle transfer data from primary database to the standby database. This approach helps us to recover data from standby database in case of any failure.Logical standby database is not the exact copy of the primary database. Logical standby uses LogMiner techniques to transform the archived redo logs into native DML statements (insert, update, delete).  This DML is transported and applied to the standby database.Primary standby database is the exact copy of primary database so it helps to minimize the ... Read More