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Articles by Fendadis John
Page 2 of 4
What are the advantages, disadvantages and restrictions of using MySQL triggers?
We must have to understand the advantages, disadvantages, and restrictions of using MySQL triggers so that we can use it effectively.AdvantagesFollowings are the advantages of using MySQL triggers −Integrity of data − With the help of MySQL trigger we can check the integrity of data in the table. In other words, MySQL triggers are the alternative way to check the integrity of data.Useful for catching errors − MySQL triggers can catch errors in business logic in the database layer.Alternative way to run scheduled tasks − Actually by using MySQL triggers we do not have to wait to run the scheduled tasks because ...
Read MoreHow MySQL SUM() function evaluates if it is used with SELECT statement that returns no matching rows?
When MySQL SUM() function used with SELECT statement that returns no matching rows then there is nothing to evaluate and it returns NULL as output. Sometimes, we thought it must return 0 as output but 0 is a number itself and for no matching rows it not significant to return 0 hence it returns NULL. To understand the above concept, consider an ‘employee_tbl’ table, which is having the following records −mysql> SELECT * FROM employee_tbl; +------+------+------------+--------------------+ | id | name | work_date | daily_typing_pages | +------+------+------------+--------------------+ | 1 | John | 2007-01-24 | 250 ...
Read MoreGenerating OTP in Java
Generate OTP is now a requirement on most of the website now-a-days. In case of additional authentication, system generates a OTP password adhering to OTP policy of the company. Following example generates a unique OTP adhering to following conditions −It should contain at least one number.Length should be 4 characters.Exampleimport java.util.Random; public class Tester { public static void main(String[] args) { System.out.println(generateOTP(4)); } private static char[] generateOTP(int length) { String numbers = "1234567890"; Random random = new Random(); char[] otp = new ...
Read MoreFlexible nature of java.lang.object
The java.lang.Object class is the root of the class hierarchy. Every class has Object as a superclass. All objects, including arrays, implement the methods of this class.Class DeclarationFollowing is the declaration for java.lang.Object class −public class ObjectClass constructorsSr.No.Constructor & Description1Object()This is the Single Constructor.Class methodsSr.No.Method & Description1protected Object clone()This method creates and returns a copy of this object.2boolean equals(Object obj)This method indicates whether some other object is "equal to" this one.3protected void finalize()This method is called by the garbage collector on an object when garbage collection determines that there are no more references to the object.4Class getClass()This method returns the ...
Read MoreFloating point operators and associativity in Java
Following programs shows the float arithmetic can cause dubious result if integer values are used using float variables.Examplepublic class Tester { public static void main(String[] args) { float a = 500000000; float b = -500000000; float c = 1; float sumabc1 = a+(b+c); float sumabc2 =(a+b)+c; System.out.println("Floating Point Arithmetic"); System.out.println("a + ( b + c ) : " + sumabc1); System.out.println("(a + b) + c : " + sumabc2); ...
Read MoreDifferent ways for Integer to String conversion in Java
Following are the different ways to convert an Integer to String in Java.Using Integer.toString(int) − Convert an int to String using static toString() method of Integer class.String b = Integer.toString(125);Using String.valueOf(int) − Convert an int to String using static valueOf() method of String class.String b = String.valueOf(125);Using new Integer(int).toString() − Convert an int to String using toString() method of Integer object.String b = new Integer(125).toString();Using DecimalFormat(pattern).format(int) − Convert an int to String using DecimalFormat.format() method.String b = new DecimalFormat("#").format(125);Using StringBuilder().toString() − Convert an int to String using StringBuilder.toString() method.String b = new StringBuilder().append(125).toString();Using StringBuffer().toString() − Convert an int to String ...
Read MoreHow to use REPLACE() function with column’s data of MySQL table?
For using it with column’s data we need to provide column name as the argument of REPLACE() function. It can be demonstrated by using ‘Student’ table data as follows −Examplemysql> Select Id, Name, Subject, REPLACE(Subject, 's', ' Science') from Student WHERE Subject = 'Computers'; +------+--------+-----------+-----------------------------------+ | Id | Name | Subject | REPLACE(Subject, 's', ' Science') | +------+--------+-----------+-----------------------------------+ | 1 | Gaurav | Computers | Computer Science | | 20 | Gaurav | Computers | Computer Science | +------+--------+-----------+-----------------------------------+ 2 rows in set (0.00 sec)
Read MoreHow can we use WHERE clause with MySQL INSERT INTO command?
We can use conditional insert i.e. WHERE clause with INSERT INTO command in the case of new row insertion. It can be done with following ways −With the help of dummy tableIn this case, we insert the value from dummy table along with some conditions. The syntax can be as follows −INSERT INTO table_name(column1, column2, column3, …) Select value1, value2, value3, … From dual WHERE [conditional predicate];Examplemysql> Create table testing(id int, item_name varchar(10)); Query OK, 0 rows affected (0.15 sec) mysql> Insert into testing (id, item_name)Select 1, 'Book' From Dual Where 1=1; Query OK, 1 row affected (0.11 sec) ...
Read MoreHow to get the difference between two arrays in JavaScript?
To get the difference between two arrays in JavaScript, try to run the following code. Here, we’re using some method like split(), indexOf(), sort(), etc to get the elements, which aren’t the same in both the arrays &mnus;ExampleLive Demo JavaScript Dates function arrDifference (arr1, arr2) { var arr = []; arr1 = arr1.toString().split(', ').map(Number); arr2 = arr2.toString().split(', ').map(Number); // ...
Read MoreAdvantages and Disadvantages of the TCP/IP Model
The advantages of TCP/IP protocol suite areIt is an industry–standard model that can be effectively deployed in practical networking problems.It is interoperable, i.e., it allows cross-platform communications among heterogeneous networks.It is an open protocol suite. It is not owned by any particular institute and so can be used by any individual or organization.It is a scalable, client-server architecture. This allows networks to be added without disrupting the current services.It assigns an IP address to each computer on the network, thus making each device to be identifiable over the network. It assigns each site a domain name. It provides name and ...
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