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You can use IFNULL() property or simple IF() with IS NULL property. The syntax is as follows −INSERT INTO yourTableName(yourColumnName1, yourColumnName2) VALUES('yourValue’', IF(yourColumnName1 IS NULL, DEFAULT(yourColumnName2), 'yourMessage'));To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table Post -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserName varchar(10), -> UserPostMessage varchar(50) NOT NULL DEFAULT 'Hi Good Morning !!!' -> ); Query OK, 0 rows affected (0.67 sec)Now you can ... Read More
The current instance of the clock in milliseconds can be obtained using the method millis() in the Clock Class in Java. This method requires no parameters and it returns the current instant of the clock in milliseconds. If the instance cannot be obtained for some reason, then the DateTimeException is thrown.A program that demonstrates this is given as follows −Example Live Demoimport java.time.*; public class Demo { public static void main(String[] args) { Clock c = Clock.systemDefaultZone(); long ms = c.millis(); System.out.println("The clock is: " + c); ... Read More
Use the fromCollection() method to create a Pair Tuple from another collection, for example, List.Let us first see what we need to work with JavaTuples. To work with Pair class in JavaTuples, you need to import the following package −import org.javatuples.Pair;Note − Steps to download and run JavaTuples program If you are using Eclipse IDE to run Pair Class in JavaTuples, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file.The following is an example −Exampleimport org.javatuples.Pair; import java.util.*; public class Demo { public static void main(String[] args) ... Read More
In a Type 3 driver, a three-tier approach is used to access databases. The JDBC clients use standard network sockets to communicate with a middleware application server. The socket information is then translated by the middleware application server into the call format required by the DBMS, and forwarded to the database server.This kind of driver is extremely flexible, since it requires no code installed on the client, a single driver can actually provide access to multiple databases. You can think of the application server as a JDBC "proxy, " meaning that it makes calls for the client application. As a ... Read More
JSP makes use of the servlet provided HttpSession Interface. This interface provides a way to identify a user across.a one-page request orvisit to a website orstore information about that userBy default, JSPs have session tracking enabled and a new HttpSession object is instantiated for each new client automatically. Disabling session tracking requires explicitly turning it off by setting the page directive session attribute to false as follows −The JSP engine exposes the HttpSession object to the JSP author through the implicit session object. Since session object is already provided to the JSP programmer, the programmer can immediately begin storing and ... Read More
This example demonstrate about How to use substring () 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 return substring value.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; public ... Read More
The allMatch() method of the IntStream class in Java returns whether all elements of this stream match the provided predicate.The syntax is as followsboolean allMatch(IntPredicate predicate)Here, the predicate parameter is a stateless predicate to apply to elements of this stream. The IntPredicate represents a predicate of one int-valued argument.The allMatch() method returns true if either all elements of the stream match the provided predicate or the stream is empty.The following is an example to implement IntStream allMatch() method in JavaExample Live Demoimport java.util.*; import java.util.stream.IntStream; public class Demo { public static void main(String[] args) { ... Read More
You can get documents with max attribute per group in a collection using $sort operator along with $group statement.To understand the concept further, let us create a collection with document. The query to create a collection with document is as follows −> db.maxAttributePerGroup.insertOne({"StudentFirstName":"John", "StudentLastName":"Smith ", "StudentAge":29, "StudentId":10}); { "acknowledged" : true, "insertedId" : ObjectId("5c76ee341e9c5dd6f1f78277") } > db.maxAttributePerGroup.insertOne({"StudentFirstName":"Carol", "StudentLastName":"Taylo r", "StudentAge":19, "StudentId":10}); { "acknowledged" : true, "insertedId" : ObjectId("5c76ee4e1e9c5dd6f1f78278") } > db.maxAttributePerGroup.insertOne({"StudentFirstName":"Adam", "StudentLastName":"Smit h", "StudentAge":34, "StudentId":20}); { "acknowledged" : true, "insertedId" : ObjectId("5c76ee631e9c5dd6f1f78279") } > db.maxAttributePerGroup.insertOne({"StudentFirstName":"Bob", "StudentLastName":"Taylor" , "StudentAge":58, "StudentId":20}); { ... Read More
You can use $nin operator for this. To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −> db.documentWithAParticularFieldValueDemo.insertOne( ... { ... ... "StudentId" : 101, ... "StudentDetails" : ... [ ... { ... "TheoryMarks": 78, ... "PracticalMarks": 91 ... }, ... { ... Read More
Dangling pointerDangling pointer is a pointer pointing to a memory location that has been freed (or deleted). There are different ways where Pointer acts as dangling pointerFunction CallThe pointer pointing to local variable becomes dangling when local variable is not static.int *show(void) { int n = 76; /* ... */ return &n; }OutputOutput of this program will be garbage address.De-allocation of memoryint main() { float *p = (float *)malloc(sizeof(float)); //dynamic memory allocation. free(p); //after calling free() p becomes a dangling pointer p = NULL; //now p no more a dangling pointer. }Variable goes ... Read More