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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 More
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 More
The LocalDateTime object can be queried as required using the query method in the LocalDateTime class in Java. This method requires a single parameter i.e. the query to be invoked and it returns the result of the query.A program that demonstrates this is given as follows −Example Live Demoimport java.time.*; import java.time.temporal.*; public class Demo { public static void main(String[] args) { LocalDateTime ldt = LocalDateTime.parse("2019-02-18T23:15:30"); System.out.println("The LocalDateTime is: " + ldt); String precision = ldt.query(TemporalQueries.precision()).toString(); System.out.println("The Precision for the LocalDateTime is: "+ precision); } }OutputThe LocalDateTime ... Read More
Remove all the elements from the list using the clear() method of the AbstractList class. After using the method, the list won’t be having any elements.The syntax is as followspublic void clear()To work with the AbstractList class, import the following packageimport java.util.AbstractList;The following is an example to implement clear() method of the AbstractlList class in JavaExample Live Demoimport java.util.ArrayList; import java.util.AbstractList; public class Demo { public static void main(String[] args) { AbstractList myList = new ArrayList(); myList.add(75); myList.add(100); myList.add(150); myList.add(200); ... Read More
To clone a collection in MongoDB, you can use the forEach() method. Let us first create a collection with a document.The query to create a collection with a document is as follows −> db.studentInformation.insertOne({"StudentName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8bc15780f10143d8431e21") } > db.studentInformation.insertOne({"StudentName":"Robert"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8bc15e80f10143d8431e22") } > db.studentInformation.insertOne({"StudentName":"James"}); { "acknowledged" : true, "insertedId" : ObjectId("5c8bc17380f10143d8431e23") }Display all documents from a collection with the help of find() method. The query is as follows −> db.studentInformation.find().pretty();The following is the output −{ "_id" : ObjectId("5c8bc15780f10143d8431e21"), "StudentName" : "Chris" } { "_id" ... Read More
In this section, we will see how to convert an integer to a string.The logic is very simple. Here we will use the sprintf() function. This function is used to print some value or line into a string, but not in the console. This is the only difference between printf() and sprintf(). Here the first argument is the string buffer. where we want to save our data.Input: User will put some numeric value say 42 Output: This program will return the string equivalent result of that number like “42”AlgorithmStep 1: Take a number from the user Step 2: Create an ... Read More
In this section we will see how to execute zombie process and orphan process in a single program in C/C++. Before going to the main discussion, let us see what are the zombie process and orphan process.Zombie ProcessesA zombie process is a process whose execution is completed but it still has an entry in the process table. Zombie processes usually occur for child processes, as the parent process still needs to read its child’s exit status. Once this is done using the wait system call, the zombie process is eliminated from the process table. This is known as reaping the ... Read More
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 More
Use trim() function to remove trailing zeroz in MySQL. Following is the syntax −select trim(yourColumnName)+0 As anyAliasName from yourTableName;Let us first create a table −mysql> create table removeTrailingZero -> ( -> Number DECIMAL(10, 4) -> ); Query OK, 0 rows affected (0.83 sec)Following is the query to insert some records in the table using insert command −mysql> insert into removeTrailingZero values(10.789); Query OK, 1 row affected (0.19 sec) mysql> insert into removeTrailingZero values(89.90); Query OK, 1 row affected (0.18 sec) mysql> insert into removeTrailingZero values(8999.70); Query OK, 1 row affected (0.20 sec) mysql> insert ... Read More
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 More