varun

varun

65 Articles Published

Articles by varun

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How to get rows and columns of 2D array in Java?

varun
varun
Updated on 24-Feb-2020 10K+ Views

Following example helps to determine the rows and columns of a two-dimensional array with the use of arrayname.length.ExampleFollowing example helps to determine the upper bound of a two dimensional array with the use of arrayname.length. public class Main {    public static void main(String args[]) {       String[][] data = new String[2][5];       System.out.println("Dimension 1: " + data.length);       System.out.println("Dimension 2: " + data[0].length);    } }OutputThe above code sample will produce the following result. Dimension 1: 2 Dimension 2: 5

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Why Java is not a pure object oriented programming language?

varun
varun
Updated on 18-Feb-2020 4K+ Views

A fully object-oriented language needs to have all the 4 oops concepts. In addition to that, all predefined and, user-defined types must be objects and, all the operations should be performed only by calling the methods of a class.Though java follows all the four object-oriented concepts,Java has predefined primitive data types (which are not objects).You can access the members of a static class without creating an object of it.Therefore, Java is not considered as fully object-oriented Technology.

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What happens if MySQL query returns no rows?

varun
varun
Updated on 13-Feb-2020 2K+ Views

From the output returned by MySQL, it is very much clear that how many rows are there in the result set along with the execution time.ExampleFor example, in the following MySQL output we can see there are 3 rows in the result set.mysql> Select * from ratelist ORDER BY Price LIMIT 3; +----+------+-------+ | Sr | Item | Price | +----+------+-------+ |  5 | T    |   250 | |  1 | A    |   502 | |  2 | B    |   630 | +----+------+-------+ 3 rows in set (0.00 sec)But suppose if MySQL query has ...

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How to call C++ functions from Java?

varun
varun
Updated on 10-Feb-2020 2K+ Views

Following are the steps to use native methods.Create a header file (.h file) for a CPP program.Create CPP fileCreate a DLLIn java code, declare the method as native, load the DLL using System.loadLibrary() method and call the method.

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How can we import the text file, having data on the same line with a separator, into MySQL table?

varun
varun
Updated on 04-Feb-2020 345 Views

Actually, we can write the data on the same line in the text file by using a separator. In this case, while importing this text file into MySQL table then we must have to use ‘LINES TERMINATED BY’ option. It can be understood with the help of the following example −Suppose we are using ‘|’ as the LINE TERMINATOR symbol in a text file as follows −id, Name, Country, Salary|105, Chum*, Marsh, USA, 11000|106, Danny*, Harrison, AUS, 12000Now while importing this text file into MySQL table then we need to mention ‘LINE TERMINATED BY’ option also in the query as ...

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How an enumeration value in MySQL can be used in an expression?

varun
varun
Updated on 03-Feb-2020 199 Views

As we know that enumeration values are associated with index values hence if we will use enumeration values in an expression then all the calculations would be done on index numbers. The following example will clarify it −mysql> Select * from Result; +-----+--------+-------+ | Id  | Name   | Grade | +-----+--------+-------+ | 100 | Gaurav | GOOD  | | 101 | Rahul  | POOR  | | 102 | Rahul  | NULL  | | 103 | Mohan  |       | +-----+--------+-------+ 4 rows in set (0.00 sec) mysql> Select SUM(Grade) from result; +------------+ | SUM(Grade) | +------------+ ...

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How can we say that in MySQL, AUTO_INCREMENT is taking precedence over PRIMARY KEY?

varun
varun
Updated on 30-Jan-2020 248 Views

This can be understood with the help of an example in which NULL value has been inserted in an AUTO_INCREMENT column and MySQL deliver a new sequence number.mysql> Create table employeeinfo(id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, Name Varchar(10)); Query OK, 0 rows affected (0.16 sec) mysql> Insert into employeeinfo(id, Name) values(NULL, 'Saurabh'); Query OK, 1 row affected (0.07 sec) mysql> Select * from employeeinfo; +----+---------+ | id | Name    | +----+---------+ | 1  | Saurabh | +----+---------+ 1 row in set (0.00 sec)As we can observe from the above example that the column ‘id’ has been ...

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How can I use any character, at the place of space, in MySQL TIMESTAMP to distinguish between date and time parts?

varun
varun
Updated on 29-Jan-2020 184 Views

We can use the only character ‘T’ (in Capital form only) at the place of space between date and time part. It can be elucidated with the help of the following example −mysql> Select TIMESTAMP('2017-10-20T06:10:36'); +----------------------------------+ | TIMESTAMP('2017-10-20T06:10:36') | +----------------------------------+ | 2017-10-20 06:10:36              | +----------------------------------+ 1 row in set (0.00 sec)

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How MySQL behaves when we use INTERVAL of time unit with CURDATE() function?

varun
varun
Updated on 28-Jan-2020 176 Views

As we know that CURDATE() only returns the date unit so it would be ambiguous to use INTERVAL of time unit with CURDATE(). MySQL always represents current date with ‘00:00:00’ time hence when we use INTERVAL of time unit with CURDATE() then such kind of time arithmetic would take this time into consideration. Following examples will clarify it −mysql> Select CURDATE() + INTERVAL 0 hour; +-----------------------------+ | curdate() + Interval 0 hour | +-----------------------------+ | 2017-10-28 00:00:00         | +-----------------------------+ 1 row in set (0.00 sec) mysql> select CURDATE() + INTERVAL 1 hour; +-----------------------------+ | curdate() ...

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What happens when MySQL encounters an out-of-range date?

varun
varun
Updated on 28-Jan-2020 544 Views

The response of MySQL on encountering out-of-range or invalid date will depend upon SQL MODE. If we have enabled ALLOW_INVALID_DATES mode then MySQL will convert the out of range values into all zeros (i.e. ‘0000:00:00 00:00:00’) and also stores the same in the table without producing any error or warning.For example, we can change SQL MODE as follows and then insert the out-of-range −mysql> set sql_mode = 'ALLOW_INVALID_DATES'; Query OK, 0 rows affected (0.00 sec) mysql> Insert into order1234(productname, quantity, orderdate) values('A', 500, '999-05-100'); Query OK, 1 row affected, 1 warning (0.13 sec) mysql> Select * from order1234; ...

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