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Articles by karthikeya Boyini
Page 129 of 142
How to upgrade MySQL server from command line?
First, you need to open the CMD with the help of shortcut key Windows+R key.After typing cmd, press the OK button. On pressing, you will get a command prompt. The screenshot is as follows −After that, you need to reach the /bin directory. Follow the below instructions. If you are a Windows user, then use the below query to reach the /bin directory.The query is as follows −mysql> select @@datadir;The following is the output displaying the path −+---------------------------------------------+ | @@datadir ...
Read MoreC++ Program to Implement Rolling Hash
Rolling hash is a hash function in which the input is hashed in a window that moves through the input.Rabin-Karp is popular application of rolling hash. The rolling hash function proposed by Rabin and Karp calculates an integer value. For a string the integer value is numeric value of a string.The Rabin–Karp string search algorithm is often explained using a very simple rolling hash function that only uses multiplications and additions −H=c1ak-1+c2ak-2+….+ cka0.Where, a is a constant, and c1, c2….ck are the input characters. In order to manipulate Huge value of H, mod n is done.AlgorithmBegin Declare a constant ...
Read MoreHow to flush output stream after writing bytes
Let us first crate OutputStream with file input.txt −FileOutputStream fileStream = new FileOutputStream("E:/input.txt"); DataOutputStream dataStream = new DataOutputStream(fileStream);Now, the writeBytes() method writes out the string to the underlying output stream as a sequence of bytes.dataStream.writeBytes("Demo text!");Flush the output stream −dataStream.flush();The following is an example. Here, our file is “E:/input.txt” and at the end we are flushing the output stream −Exampleimport java.io.DataOutputStream; import java.io.FileOutputStream; public class Demo { public static void main(String[] args) throws Exception { FileOutputStream fileStream = new FileOutputStream("E:/input.txt"); DataOutputStream dataStream = new DataOutputStream(fileStream); dataStream.writeBytes("Demo text!"); ...
Read MoreHow to display message from a stored procedure?
To display message from stored procedure on the basis of conditions, let us use IF-ELSE condition −mysql> DELIMITER // mysql> CREATE PROCEDURE showMessage(value int, Name varchar(20)) BEGIN IF(value > 100) then SELECT CONCAT("HELLO", " ", Name); ELSE SELECT CONCAT("BYE", " ", Name); END IF; END // Query OK, 0 rows affected (0.18 sec) mysql> DELIMITER ;Case 1 − Call the stored procedure using CALL command, when value is more than 100 −call showMessage(200, 'John');This will produce ...
Read MoreMySQL query to select too many rows?
You can use LIMIT for this, which is used to fetch limited number of records. Let us first create a table −mysql> create table DemoTable ( Id int, Name varchar(20) ); Query OK, 0 rows affected (0.53 sec)Insert records in the table using insert command −mysql> insert into DemoTable values(10, 'John'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(11, 'Chris'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(12, 'David'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(13, 'Carol'); Query OK, 1 row affected (0.13 sec) mysql> ...
Read MoreReplace dot with comma on MySQL SELECT?
To replace dot with comma on SELECT, you can use REPLACE(). Following is the syntax −select replace(yourColumnName, '.' , ', ' ) from yourTableName;Let us first create a table −mysql> create table DemoTable ( Value float ); Query OK, 0 rows affected (0.63 sec)Insert records in the table using insert command −mysql> insert into DemoTable values(4.56); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(456.23); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(1078.3); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values(2000.50); Query OK, 1 row affected (0.26 sec) mysql> ...
Read MoreHow to remove Duplicate Records except a single record in MySQL?
You can use DELETE command with some condition for this since we need to keep one record and delete rest of the duplicate records.Let us first create a table −mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(40) ); Query OK, 0 rows affected (0.48 sec)Insert records in the table using insert command −mysql> insert into DemoTable(StudentName) values('John'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(StudentName) values('Carol'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(StudentName) values('Sam'); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable(StudentName) ...
Read MoreHow to use Iterator to loop through the Map key set?
First, create a HashMap, which is to be iterated −Mapmap = new LinkedHashMap(); map.put("Jack", "0"); map.put("Tim", "1"); map.put("David", "2"); map.put("Tom", "3"); map.put("Kevin", "4");Now, use Iterator to map through keyset −Iterator iterator = map.keySet().iterator();Iterate through all the pairs −while (iterator.hasNext()) { String resKey = (String) iterator.next(); System.out.println("Rank of " + resKey + " is " + map.get(resKey)); }Example Live Demoimport java.util.Iterator; import java.util.LinkedHashMap; import java.util.Map; public class Demo { public static void main(String[] args) { Mapmap = new LinkedHashMap(); map.put("Jack", "0"); map.put("Tim", "1"); map.put("David", "2"); ...
Read MoreSet MySQL int column to auto increment by 1 beginning at 10000?
Let us first create a table. Here, we have set UserId as AUTO_INCREMENT PRIMARY KEY −mysql> create table DemoTable ( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY ); Query OK, 0 rows affected (0.72 sec)Following is the query to set int column to auto increment by 1 beginning at 10000 −mysql> alter table DemoTable AUTO_INCREMENT=10000; Query OK, 0 rows affected (0.31 sec) Records: 0 Duplicates: 0 Warnings: 0Insert records in the table using insert command −mysql> insert into DemoTable values(); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(); Query OK, 1 row affected (0.19 sec) ...
Read MoreHow to use poll() in android PriorityBlockingQueue?
Before getting into the example, we should know what PriorityBlockingQueue is. It is an unbounded queue and follows the same order as a priority queue. The main usage of priority blocking queue is, it going to handle out of memory error.This example demonstrates about How to use poll() in android PriorityBlockingQueueStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code, we have taken a text view to show PriorityBlockingQueue ...
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