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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to fix poor performance of INFORMATION_SCHEMA.key_column_usage in MySQL?
You can use GLOBAL variable as shown below −SET global innodb_stats_on_metadata =0;After including the above syntax, the INFORMATION_SCHEMA.key_column_usage will take less time and that would improve the performance.The query is as follows −mysql> set global innodb_stats_on_metadata =0; Query OK, 0 rows affected (0.00 sec) mysql> SELECT REFERENCED_TABLE_NAME,TABLE_NAME,COLUMN_NAME,CONSTRAINT_SCHEMA -> FROM INFORMATION_SCHEMA.key_column_usage;The following is the output −It returns 674 rows in 0.28 seconds.
Read MoreC++ Program to Implement Hash Tables Chaining with Doubly Linked Lists
A hash table is a data structure which is used to store key-value pairs. Hash function is used by hash table to compute an index into an array in which an element will be inserted or searched.This is a C++ program to Implement Hash Tables chaining with doubly linked lists.AlgorithmFor insert:Begin Declare Function insert(int k, int v) int hash_v= HashFunc(k) HashTableEntry *en = ht[hash_v] if (en == NULL) en = new HashTableEntry en->d = v en->k = k ...
Read MoreWhat are the popular Crypto Currencies in circulation?
Bitcoin, invented by Satoshi Nakamoto in 2008 has ushered new waves in the field of cryptocurrencies. Inspired by Bitcoins and decentralized peer-to-peer network, there are many digital currencies that came into the world to change the global economy.Let us first understand what is a cryptocurrency? Cryptocurrencies are the digital currencies which are generated, stored and transacted digitally. The most important feature of cryptocurrency which makes it different from fiat currency is, that it is not created or maintained by any single central authority. It is created and maintained through a decentralized system which is maintained by the miners. The miners ...
Read MoreHow to get the greatest of two columns values in MySQL?
In order to get the greatest of two columns values in MySQL, you need to use GREATEST() function. Following is the syntax:select greatest(yourColumnName1, yourColumnName2) AS anyAliasName from yourTableName; Let us first create a table:mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Number1 int, Number2 int ); Query OK, 0 rows affected (0.63 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable(Number1, Number2) values(1000, 10000); Query OK, 1 row affected (0.49 sec) mysql> insert into DemoTable(Number1, Number2) values(600, 900); Query OK, 1 row affected (0.12 sec) mysql> ...
Read MoreHow to store list in a txt file and read list from txt file in android?
This example demonstrates How to store list in a txt file and read list from txt file in android.Step 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 editext and button. When the user clicks on the button, it will take data from edit text and store in internal storage as /data/data//files/text/sample.txt. It going to append ...
Read MoreHow to use Tree set in Android?
This example demonstrates about How to use Tree set in AndroidStep 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 the name and record number as Edit text, when the user clicks on save button it will store the data into ArrayList. Click on the refresh button to get the ...
Read MoreHow to use compareTo () in Android textview?
This example demonstrate about How to use compareTo () in Android textview.Step 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 name as Edit text, when user click on button it will take data and compare with sairam string.Step 3 − Add the following code to src/MainActivity.javapackage com.example.myapplication; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; ...
Read MoreHow to get day of month, day of year and day of week in android using offset date time API class?
This example demonstrate about How to get day of month, day of year and day of week in android using offset date time API class.Step 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 textview to show day of month, day of year and day of the week.Step 3 − Add the following code to src/MainActivity.javapackage com.example.myapplication; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.TextView; import ...
Read MoreHow to revert rows to default column value in MySQL?
To revert rows to default column value, let us first create a demo tablemysql> create table defaultDemo -> ( -> Id int -> ); Query OK, 0 rows affected (0.48 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into defaultDemo values(10); Query OK, 1 row affected (0.25 sec) mysql> insert into defaultDemo values(20); Query OK, 1 row affected (0.13 sec) mysql> insert into defaultDemo values(30); Query OK, 1 row affected (0.14 sec) mysql> insert into defaultDemo values(40); Query OK, 1 row affected (0.11 sec) mysql> insert into defaultDemo values(80); Query OK, ...
Read MoreAndroid scan wifi networks programmatically
This example demonstrate about How to scan wifi networks programmatically.Step 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. Step 3 − Add the following code to src/MainActivity.javapackage com.example.myapplication; import android.Manifest; import android.content.Context; import android.content.IntentFilter; import android.content.pm.PackageManager; import android.net.wifi.WifiManager; import android.os.Build; import android.support.annotation.NonNull; import android.support.v4.app.ActivityCompat; import android.support.v4.content.ContextCompat; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.ListView; import android.widget.Toast; public class MainActivity extends AppCompatActivity { private ListView wifiList; ...
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