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Programming Articles
Page 2512 of 2547
How to insert rows into a ResultSet in JDBC?
You can retrieve the contents of a table as a ResultSet and, insert a new row to it directly. To do so, first of all, you need to make sure your ResultSet is updatable.The moveToInsertRow() method of the ResultSet interface navigates the cursor to the position where you need to insert the next record. Therefore, move the cursor to the appropriate position to insert a row using this method.The updateXXX() methods of the ResultSet interface allows you to insert/update values into the ResultSet object.Add values to the new row using these methods for example if you need to insert an ...
Read MoreHow to call a stored procedure that returns output parameters, using JDBC program?
A. Stored procedures are sub routines, segment of SQL statements which are stored in SQL catalog. All the applications that can access Relational databases (Java, Python, PHP etc.), can access stored procedures.Stored procedures contain IN and OUT parameters or both. They may return result sets in case you use SELECT statements. Stored procedures can return multiple result sets.You can call a stored procedure using the following syntax:CALL procedure_name (input_parameter1, input_parameter2, input_parameter3)JDBC provides a standard stored procedure SQL escape syntax using which you can procedures in all RDBMSsTo call a stored procedure using a JDBC program you need to:Register the driver: ...
Read MoreConvert IntStream to String in Java
If you have IntStream with ASCII values, then easily convert it to string using the below given example.For IntStream class, import the following packageimport java.util.stream.IntStream;Let’s say the following is our IntStreamIntStream stream = "Example".chars();Now, convert the IntStream to stringString str = stream.collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append).toString();The following is an example to convert IntStream to String in JavaExampleimport java.util.stream.IntStream; class Demo { public static void main(String[] args) { IntStream stream = "Example".chars(); System.out.println("The ASCII values..."); String str = stream.collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append).toString(); System.out.println("The ...
Read MoreIntStream mapToLong() method in Java
The mapToLong() function in IntStream class returns a LongStream consisting of the results of applying the given function to the elements of this stream.The syntax is as follows.LongStream mapToLong(IntToLongFunction mapper)Here, the parameter mapper is a stateless function to apply to each element.Create an IntStream with some elements in the Stream.IntStream intStream = IntStream.of(50, 100, 150, 200);Now create a LongStream and use the mapToLong() with a condition.LongStream longStream = intStream.mapToLong(num → (long)num);The following is an example to implement IntStream mapToLong() method in Java.Exampleimport java.util.*; import java.util.stream.IntStream; import java.util.stream.LongStream; public class Demo { public static void main(String[] args) { ...
Read MoreHow to create a function in a database using JDBC API?
Like procedures, you can also create function in a database and store them.SyntaxFollowing is the syntax of creating a function in a(MySQL) database:CREATE FUNCTION Function_Name(input_arguments) RETURNS output_parameter BEGIN declare variables; statements . . . . . . . . . . return data_type; ENDTo create a function in a database using JDBC API you need to:Register the driver: class using the registerDriver() method of the DriverManager class. Pass the driver class name to it, as parameter.Establish a connection: Connect ot the database using the getConnection() method of the DriverManager class. Passing ...
Read MoreHow to convert string to char array in C++?
This is a C++ program to convert string to char array in C++. This can be done in multiple different waysType1AlgorithmBegin Assign a string value to a char array variable m. Define and string variable str For i = 0 to sizeof(m) Copy character by character from m to str. Print character by character from str. EndExample#include #include using namespace std; int main() { char m[]="Tutorialspoint"; string str; int i; for(i=0;i
Read MoreC++ program to Check if a Given Binary Tree is an AVL Tree or Not
AVL tree is a self-balancing Binary Search Tree where the difference between heights of left and right subtrees cannot be more than one for all nodes.This is a C++ program to check if a given Binary Tree is an AVL Tree or not.AlgorithmBegin function AVL() returns true if the given tree is AVL otherwise false. if(root == NULL) return 1 leftheight = height(root->left) rightheight = height(root->right) if(abs(leftheight-rightheight) left) && AVL(root->right)) return 1 return 0 EndExample#include using namespace std; class nod { //node declaration public: int data; ...
Read MoreWhy C++ does not have a virtual constructor?
The virtual mechanism works only when we have a base class pointer to a derived class object.In C++, constructor cannot be virtual, because when constructor of a class is executed there is no virtual table in the memory, means no virtual pointer defined yet. So, the constructor should always be non-virtual.But virtual destructor is possible. Here is an exampleExample#include using namespace std; class b { public: b() { cout
Read MoreHow to generate different random numbers in a loop in C++?
Let us see how to generate different random numbers using C++. Here we are generating random numbers in range 0 to some value. (In this program the max value is 100).To perform this operation we are using the srand() function. This is in the C++ library. The function void srand(unsigned int seed) seeds the random number generator used by the function rand.The declaration of srand() is like below −void srand(unsigned int seed)It takes a parameter called seed. This is an integer value to be used as seed by the pseudo-random number generator algorithm. This function returns nothing.To get the number ...
Read MoreHow are virtual functions implemented in C++?
Virtual functions in C++ used to create a list of base class pointers and call methods of any of the derived classes without even knowing kind of derived class object. Virtual functions are resolved late, at runtime.Here is an implementation of virtual function in C++ program −Example#include using namespace std; class B { public: virtual void s() { //virtual function cout
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