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Articles on Trending Technologies
Technical articles with clear explanations and examples
What MySQL returns if we provide an empty string for padding with other string in LPAD() or RPAD() functions?
Suppose if we provide an empty string for padding on LPAD() or RPAD() functions then MySQL will return NULL as output. Following example will demonstrate it −Examplemysql> Select LPAD('ABCD',22,''); +--------------------+ | LPAD('ABCD',22,'') | +--------------------+ | NULL | +--------------------+ 1 row in set (0.00 sec) mysql> Select RPAD('ABCD',22,''); +--------------------+ | RPAD('ABCD',22,'') | +--------------------+ | NULL | +--------------------+ 1 row in set (0.00 sec)
Read MoreHow MySQL evaluates the blank line between two lines written in the text file while importing that text file into MySQL table?
Suppose if there is a blank line between two line written in the text file then MySQL evaluates it as the data line while importing that text file into MySQL table. It can be understood with the help of the following example −ExampleSuppose we are having a blank line between two lines in a text file named ‘A.txt’ as follows −105, Chum, USA, 11000 106, Danny, AUS, 12000Now we can write the following query to import the data from text file into MySQL table −mysql> LOAD DATA LOCAL INFILE 'd:\A.txt' INTO table employee10_tbl FIELDS TERMINATED BY ', '; Query OK, ...
Read MoreHow to insert new string within a string subsequent to removing the characters from the original string by using MySQL function?
We can use MySQL INSERT() function to insert new string within a string after removing the characters from the original string.SyntaxINSERT(original_string, @pos, @len, new_string)Here, original_string is the string in which we want to insert new string at the place of some specific number of characters.@pos is the position at which the insertion of new string should start.@len is the number of characters should delete from the original string. The starting point of deletion of characters is value of @pos.New_string is the string we want to insert into the original string.Examplemysql> Select INSERT('Yash Sharma', 5, 7, ' Pal'); +----------------------------------+ | ...
Read MoreHow can we upload the changed value, rather than written in a text file, of column(s) while importing that text file into MySQL table?
Suppose if we want to upload the changed value rather than the value written in a text file then we need to use user variables along with the SET command. It can be understood with the help of the following example −ExampleSuppose we are having the following data in ‘A.txt’ −105, Chum, USA, 11000 106, Danny, AUS, 12000But we want to upload the value of salary after adding 500 to it at the time of importing it without changing the value of salary in a text file then it can be done with the help of the following query by ...
Read MoreWhat MySQL returns on running the INSERT INTO statement without giving the column name and values both?
When we run the INSERT INTO statement without giving the columns name/s and values both then MySQL will store NULL as the value of the column/s of table. Consider the example given below in which we have created a table ‘Student’ with the following query −mysql> Create table Student(RollNO INT, Name Varchar(20), Class Varchar(15)); Query OK, 0 rows affected (0.17 sec)Now, we can run INSERT INTO statement without giving the columns name/s and values both as follows −mysql> Insert into Student() Values(); Query OK, 1 row affected (0.02 sec)We can see from the query below MySQL stores NULL as the ...
Read MoreHow can we change the default MySQL database to the given database?
Suppose currently we are using a tutorial database so it would be the default MySQL database for subsequent queries. Now, with the help of USE db_name statement, we can change the default database to other given database subsequent queries.mysql> USE Sample Database changedThe database has been changed to Sample from the tutorial. To verify this we can run the following command −mysql> select database(); +------------+ | database() | +------------+ | sample | +------------+ 1 row in set (0.00 sec)
Read MoreHow to access Java package from another package
You can understand it using an example where a Boss class is defined in payroll package.package payroll; public class Boss { public void payEmployee(Employee e) { e.mailCheck(); } }if the Employee class is not in the payroll package? The Boss class must then use one of the following techniques for referring to a class in a different package.The fully qualified name of the class can be used. For example −payroll.EmployeeThe package can be imported using the import keyword and the wild card (*). For example −import payroll.*;The class itself can be imported using the import ...
Read MoreHow to use sub-package in Java?
Subpackages are similar to sub-directories. Consider an example. The company had a com.apple.computers package that contained a Dell.java source file, it would be contained in a series of subdirectories like this −....\com\apple\computers\Dell.javaAt the time of compilation, the compiler creates a different output file for each class, interface, and enumeration defined in it. The base name of the output file is the name of the type, and its extension is .class.For example −// File Name:Dell.java package com.apple.computers; public class Dell { } class Ups { }Now, compile this file as follows using -d option −$javac -d.Dell.javaThe files will be compiled as ...
Read MoreHow to load classes at runtime from a folder or Java package
Using CLASSPATH, you can load any classes at runtime.Like the .java source files, the compiled .class files should be in a series of directories that reflect the package name. However, the path to the .class files does not have to be the same as the path to the .java source files. You can arrange your source and class directories separately, as −\sources\com\apple\computers\Dell.java \classes\com\apple\computers\Dell.classBy doing this, it is possible to give access to the classes directory to other programmers without revealing your sources. You also need to manage source and class files in this manner so that the compiler and the ...
Read MoreJava constructor return a value but, what?
No. Java constructor cannot return a value. If required, just create a method which calls the required constructor and returns the required value. See the example below.public class Tester { public Tester(){} public static Tester getInstance(){ Tester tester = new Tester(); return tester; } }
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