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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to select data from a table where the table name has blank spaces in MYSQL?
You need to use backticks around the table name where the table name has blank space. Let us first create a table. Here, we have used backtick −mysql> create table `Demo Table138` ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Price int ); Query OK, 0 rows affected (0.47 sec)Insert records in the table using insert command −mysql> insert into `Demo Table138`(Price) values(450); Query OK, 1 row affected (0.18 sec) mysql> insert into `Demo Table138`(Price) values(499); Query OK, 1 row affected (0.16 sec) mysql> insert into `Demo Table138`(Price) values(199); Query OK, 1 row affected (0.17 sec) mysql> insert into ...
Read MoreMerits of I/O-mapped I/O and demerits of memory-mapped I/O
Before having a discussion regarding the merits of I/O mapped I/O and demerits of memorymapped I/O, let us have a generic discussion regarding the difference between I/O mapped I/O and memory mapped I/O.In Memory Mapped Input Output −We allocate a memory address to an Input Output device.Any instructions related to memory can be accessed by this Input Output device.The Input Output device data are also given to the Arithmetic Logical Unit.Input Output Mapped Input Output −We give an Input Output address to an Input Output device.Only IN and OUT instructions are accessed by such devices.The ALU operations are not directly ...
Read MorePrevent negative numbers in MySQL?
To prevent negative numbers in MySQL, you need to use INT UNSIGNED. Let’s say you created a table with a column as int i.e. UserGameScores heremysql> create table preventNegativeNumberDemo - > ( - > UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > UserName varchar(20), - > UserGameScores int - > ); Query OK, 0 rows affected (1.74 sec)Now if you need to prevent negative numbers in it, modify the same column with INT UNSIGNEDmysql> alter table preventNegativeNumberDemo modify column UserGameScores INT UNSIGNED NOT NULL; Query OK, 0 rows affected (3.32 sec) Records: 0 ...
Read MoreWhat is the difference between the TYPE_SCROLL_INSENSITIVE and TYPE_SCROLL_SENSITIVE ResultSets in JDBC?
In the TYPE_SCROLL_INSENSITIVE ResultSet, the cursor moves in forward or backward directions. This type of ResultSet is insensitive to the changes that are made in the database i.e. the modifications done in the database are not reflected in the ResultSet.Which means if we have established a connection with a database using a JDBC program and retrieved a ResultSet holding all the records in a table named SampleTable. Meanwhile, if we have added some more records to the table (after retrieving getting the ResultSet), these recent changes will not be reflected in the ResultSet object we previously obtained.In the TYPE_SCROLL_SENSITIVE ResultSet, ...
Read MoreHow do I prevent Android taking a screenshot when my app goes to the background?
In some situations, we should not allow to take screen shots of our application. This example demonstrate about how do I prevent Android taking a screenshot when my app goes to the background.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 text view for some sample view.Step 3 − Add the following code to src/MainActivity.javapackage com.example.andy.myapplication; import android.os.Build; import android.os.Bundle; import android.support.annotation.RequiresApi; import android.support.v7.app.AppCompatActivity; import ...
Read MoreJava Program to convert a list to a read-only list
Let’s say the following is our list which isn’t read-only:List < Integer > list = new ArrayList < Integer > (); list.add(10); list.add(20); list.add(30); list.add(40); list.add(50); list.add(20); list.add(40); list.add(50);Convert the above list to Read-only:list = Collections.unmodifiableList(list);On conversion, now you won’t be add or remove elements from the List. Let us see an example:The following program will give an error because we first update the list to read only and then try to remove an element from it, which is not possible now. The reason is we have converted the list to readonly and you cannot add or remove element from ...
Read MoreRun SQL file in MySQL database from terminal?
To run SQL file in database, you need to use below syntax:mysql -u yourUserName -p yourDatabaseName < yourFileName.sqlTo understand the above syntax, let us open command prompt using windows+R shortcut key.The snapshot is as follows:After pressing OK button, you will get a command prompt. The snapshot is as follows:Now reach the bin directory, the snapshot is as follows:Here is my file ‘mydb.sql’ which is located in bin directory. The snapshot and content of SQL file is as follows:Now you can type the above syntax which I have discussed to run SQL file. The snapshot of command is as follows:Now you ...
Read MoreWhat is ODBC?
ODBC stands for Oracle Database Connectivity. It is an API which is used to access different databases.The OFBC driver uses the Open Database connectivity interface provided by Microsoft to communicate with the databases. It is independent of Databases and platforms and operating systems. Once you develop an application using ODBC you can run it on other platforms with little change in Data access code. ODBC uses SQL syntax and it is based on Open call level interface.
Read MoreHow to get current Bluetooth address in android?
This example demonstrates How to get current Bluetooth address 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 text view to show Bluetooth address.Step 3 − Add the following code to src/MainActivity.javapackage com.example.myapplication; import android.bluetooth.BluetoothManager; import android.content.Context; import android.net.ConnectivityManager; import android.net.Network; import android.os.Build; import android.os.Bundle; import android.os.health.SystemHealthManager; import android.provider.Telephony; import android.support.annotation.RequiresApi; import android.support.v7.app.AppCompatActivity; import android.telephony.SmsManager; import android.view.View; import android.view.WindowManager; import android.widget.TextView; public ...
Read MoreHow do we use runOnUiThread in Android?
Before getting into example, we should know what is runOnUiThread() in android. Sometimes Main thread performs some heavy operations. if user wants to add some extra operations on UI, it will get load and provides ANR. Using runOnUiThread going to do back ground operations on worker thread and update the result on main thread.This example demonstrate about How do we use runOnUiThread 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. ...
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