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Articles by radhakrishna
Page 5 of 7
Can we overload the main method in Java?
Yes, we can overload the main method in Java, but When we execute the class JVM starts execution with public static void main(String[] args) method. Example public class Sample{ public static void main(){ System.out.println("This is the overloaded main method"); } public static void main(String args[]){ Sample obj = new Sample(); obj.main(); } } Output This is the overloaded main method
Read MoreWhat would be the result if we perform any kind of arithmetic calculations in MySQL having one of the arguments as NULL?
MySQL always throws NULL as the result of arithmetic calculations in which one of the arguments is NULL. Consider the following example having NULL as an argument with addition, subtraction, multiplication, and division −mysql> Select 10*NULL; +---------+ | 10*NULL | +---------+ | NULL | +---------+ 1 row in set (0.12 sec) mysql> Select 10+NULL; +---------+ | 10+NULL | +---------+ | NULL | +---------+ 1 row in set (0.00 sec) mysql> Select 10-NULL; +---------+ | 10-NULL | +---------+ | NULL | +---------+ 1 row in set (0.07 sec) mysql> Select 10/NULL; +---------+ | 10/NULL | +---------+ ...
Read MoreHow can we use two columns with MySQL WHERE clause?
It is very rarely used to use two columns of the same table in WHERE clause but still we can perform a query with two columns of the same table. Consider the below example −mysql> Select F_name, L_name -> From Customer -> where F_name = L_name; Empty set (0.00 sec)Here we are using both the columns(F_Name and L_Name) from the same table(Customer) hence the result is an Empty set.
Read MoreHow can I write a MySQL stored function that calculates the factorial of a given number?
Following is the example of a stored function that can calculate the factorial of a given number −CREATE FUNCTION factorial (n DECIMAL(3,0)) RETURNS DECIMAL(20,0) DETERMINISTIC BEGIN DECLARE factorial DECIMAL(20,0) DEFAULT 1; DECLARE counter DECIMAL(3,0); SET counter = n; factorial_loop: REPEAT SET factorial = factorial * counter; SET counter = counter - 1; UNTIL counter = 1 END REPEAT; RETURN factorial; END // mysql> Select Factorial(5)// +--------------+ | Factorial(5) | +--------------+ | 120 | +--------------+ 1 row in set (0.27 sec) mysql> Select Factorial(6)// +--------------+ | Factorial(6) | +--------------+ | 720 | +--------------+ 1 row in set (0.00 sec)
Read MoreWhat are the special security requirements for using stored procedures and functions together with replication?
Actually, a MySQL slave server has the authority to execute any statement read from a master's MySQL server binary log, hence some special security constraints exist for using stored functions with replication. If replication or binary logging in general (for the purpose of point-in-time recovery) is active, then MySQL DBAs have two security options open to them −Option of SUPER privilegeAny user wishing to create stored functions must be granted the SUPER privilege by DBA.log_bin_trust_function_creators modeActually, log_bin_trust_function_creators enables anyone with the standard CREATE ROUTINE privilege to create stored functions hence a DBA can set the log_bin_trust_function_creators system variable to 1.
Read MoreWhat are the different modes of parameters used by MySQL stored procedure?
Parameters make the stored procedure more useful and flexible. In MySQL, we have the following three kinds of modes −IN modeIt is the default mode. When we define an IN parameter in a stored procedure, the calling program has to pass an argument to the stored procedure. The value of an IN parameter is protected which means that even the value of the IN parameter is changed inside the stored procedure; its original value is retained after the stored procedure ends.OUT modeThe value of an OUT parameter can be changed inside the stored procedure and its new value is passed back to the calling ...
Read MoreHow can we get "MySQL server-side help"?
MySQL provides help command to get server-side help. The syntax of this command is as follows −mysql> help search_stringMySQL uses the argument of help command as the search string for accessing the contents of MySQL reference manual. The search will fail if there would be no match for the search string.For example − suppose I want to get server-side help regarding INTEGER data type then the command for the same would be as follows −mysql> help INTEGER Name: 'INTEGER' Description: INTEGER[(M)] [UNSIGNED] [ZEROFILL] This type is a synonym for INT. URL: http://dev.mysql.com/doc/refman/5.5/en/numeric-type-overview.html
Read MoreHow can we set up a MySQL User account by using SQL GRANT statement?
We can also add user account by using GRANT SQL command. It can be illustrated by using the following example −ExampleIn this example, we will add user Zara with password zara123 for a particular database,which is named as TUTORIALS.root@host# mysql -u root -p password; Enter password:******* mysql> use mysql; Database changed mysql> GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP -> ON TUTORIALS.* -> TO 'zara'@'localhost' -> IDENTIFIED BY 'zara123';The above statements will also create an entry in the MySQL database table called as a user.
Read MoreWhich tables are used to control the privileges of MySQL database server?
When we install MySQL server, a database named MySQL created automatically. This MySQL database contains five main grant tables with the help of which MySQL server can control the privileges of MySQL database server. These tables are as follows −user tableThis table contains user account and global privileges columns. MySQL uses the user table to either accept or reject a connection from a host. A privilege granted in the user table is effective to all databases on the MySQL server.db tableThis table contains database-level privileges. MySQL uses the db table to determine which database a user can access and from which host. ...
Read MoreHow can we use SET statement to assign a SELECT result to a MySQL user variable?
For using the SET statement to assign a SELECT result to a user variable we need to write the SELECT statement as a subquery within parentheses. The condition is that the SELECT statement must have to return a single value. To make it understand we are using the data from ‘Tender’ table which is as follows −mysql> select * from Tender; +----+---------------+--------------+ | Sr | CompanyName | Tender_value | +----+---------------+--------------+ | 1 | Abc Corp. | 250.369003 | | 2 | Khaitan Corp. | 265.588989 | | 3 | Singla group. | 220.255997 | ...
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