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Articles by karthikeya Boyini
Page 100 of 143
How to build a java web application using SAP platform and HANA database?
You would require to change the connection.properties file of your local Tomcat Server (Server > Java Web Tomcat 8 Server-config/config_master/connection_data), to point to the HANA database.Here are the usual parameters that need to be configured for HANA databasejavax.persistence.jdbc.driver=com.sap.db.jdbc.Driver javax.persistence.jdbc.url=jdbc:sap://:/?reconnect=true&autocommit=false javax.persistence.jdbc.user=db-user javax.persistence.jdbc.password=db-pass eclipselink.target-database=HANA
Read MoreWhat MySQL returns, if the length of the original string is greater than the length specified as an argument in LPAD() or RPAD() functions?
In this case, MySQL will not pad anything and truncate the characters from the original string up to the value of length provided as the argument in LPAD() or RPAD() functions.Examplemysql> Select LPAD('ABCD',3,'*'); +--------------------+ | LPAD('ABCD',3,'*') | +--------------------+ | ABC | +--------------------+ 1 row in set (0.00 sec) mysql> Select RPAD('ABCD',3,'*'); +--------------------+ | RPAD('ABCD',3,'*') | +--------------------+ | ABC | +--------------------+ 1 row in set (0.00 sec)We can observe from the above example that both the functions do not pad ‘*’ and truncate the original string up to the length specified i.e. 3 as the argument.
Read MoreWhat is the use of MySQL BINARY keyword while performing string comparison?
When MySQL performs string comparison then it is not case-sensitive but with the help of BINARY keyword, MySQL can perform case-sensitive string comparison. It is because BINARY keyword instructs MySQL to compare the characters in the string using their underlying ASCII values rather than just their letters. It can be illustrated with the following example from table ‘Student_info’ having the following data −mysql> Select * from student_info; +------+---------+------------+------------+ | id | Name | Address | Subject | +------+---------+------------+------------+ | 101 | YashPal | Amritsar | History | | 105 | Gaurav | Chandigarh | ...
Read MoreWhy should we not use group functions with non-group fields without GROUP BY clause in MySQL SELECT query?
It is because without GROUP BY clause the output returned by MySQL can mislead. We are giving following example on the ‘Student’ table given below, to demonstrate it −mysql> Select * from Student; +------+---------+---------+-----------+ | Id | Name | Address | Subject | +------+---------+---------+-----------+ | 1 | Gaurav | Delhi | Computers | | 2 | Aarav | Mumbai | History | | 15 | Harshit | Delhi | Commerce | | 20 | Gaurav | Jaipur | Computers | +------+---------+---------+-----------+ 4 rows in set (0.00 sec) mysql> ...
Read MoreHow can we create a new MySQL table by selecting specific column/s from another existing table?
As we know that we can copy the data and structure from an existing table by CTAS script. If we want to select some specific column/s from another table then we need to mention them after SELECT. Consider the following example in which we have created a table named EMP_BACKUP1 by selecting a specific column ‘name’ from already existing table ‘Employee’ −mysql> Create table EMP_BACKUP1 AS Select name from employee; Query OK, 3 rows affected (0.25 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> Select * from EMP_BACKUP1; +--------+ | name | +--------+ | Ram | | ...
Read MoreWhat happens if I will delete a row from MySQL parent table?
While deleting the row from the parent table, if the data of that row is used in the child table then MySQL will throw an error because of the failure of FOREIGN KEY constraint. It can be understood with the example of two tables named ‘customer’ and ‘orders’. Here, ‘customer’ is the parent table and ‘orders’ is the child table. We cannot delete a row, that is used in child table ‘orders’, from the ‘customer’ table. It can be demonstrated by deleting the values from the parent table as follows −mysql> Select * from Customer; +----+--------+ | id | name ...
Read MoreHow to Install a Software on Linux Using Yum Command?
In this article, we will learn about “how to use the Yum command” for installing the packages. Also note that, the repositories on the Cent OS 6.7 YUM (Yellowdog Update Modified) is a tool used to develop by Redhat. You can use this materials for learning the YUM.Managing Software with YUMUse the yum utility to install or modify the software on your system in the following ways –New software installation from repositories.Installing software from an individual package file.Updating the existing software on your system.Removing unwanted software from your system.Installing Software from a Package FileThe yum commands used in this is ...
Read MoreHow to Increase Swap Space on Linux Ubuntu?
In this article, we will learn how to increase the swap space, which will solve the memory errors in applications. This will cover how to add a swap file to an Ubuntu Linux.Anyway, this is recommended to utilize the spinning hard disk drivers for swap as SSD can cause issues with hardware degradation over time. Due to this reason, do not enable swap on Cloud where the SSD storage is provided.What is Swap file?The Swap is a place where the OS can store temporary data as it can no longer holds in RAM. Basically, this will increase the ability of ...
Read MoreHow to go from Zero to Internet Hero using IFTTT Technology?
Isn’t it great to receive an advance notification to pack your umbrella, as it will rain tomorrow? Or else, remind yourself to silence your phone, when you get to work? If you will understand this, then that will reboot your life with a kick start. In short, we are talking about IFTTT (If This, Then That) technology. Confused? Well, it is a super tool that works as a coordinator for your apps and produce results based on your “if” logic. Let’s simplify it further.Suppose you want to auto update a status on Facebook as soon as you post a picture ...
Read MoreHow to Format a Hard Disk on Linux OS
In this article, we will learn how to add a new hard disk drive to Linux OS, Assuming the drive is visible to the BIOS, it should automatically be detected by the operating system. Typically, the disk drives in a system is assigned to a device name beginning with ‘hd’ or ‘sd’ followed by a letter to indicate the device number. For example, the first device might be /dev/sda, the second /dev/sdb and so on.The following is the output from a system with only one physical disk drive.# ls /dev/sd* /dev/sda /dev/sda1 /dev/sda2 /dev/sdbThis shows that the disk drive represented ...
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