Vrundesha Joshi has Published 378 Answers

What uses are there for “placement new” in C++?

Vrundesha Joshi
Vrundesha Joshi
Published on 03-Apr-2019 08:49:13
In this section we will see what is the placement new operator in C++. This placement new is another variation of new operator. The normal new operator performs two things. It allocates memory, and then constructs an object in allocated memory.The new operator allocates memory in the heap section and ... Read More

How do I add two numbers without using ++ or + or any other arithmetic operator in C/C++?

Vrundesha Joshi
Vrundesha Joshi
Published on 03-Apr-2019 08:23:52
In this article we will see how to add two numbers without using arithmetic operators like +, ++, -, or --.To solve this problem, we can solve them using binary adder logic. In that case we were designed half adder and full adder. These adders can add one bit binary ... Read More

How to connect to a MongoDB database using a JDBC program?

Vrundesha Joshi
Vrundesha Joshi
Published on 02-Apr-2019 13:15:29
MongoDB is a cross-platform, document oriented database that provides, high performance, high availability, and easy scalability. MongoDB works on concept of collection and document.Before you start connecting MongoDB in you need to make sure that you have MongoDB JDBC driver. If not, download the jar from the path Download mongo.jar ... Read More

How to get the current value of a particular row from a database using JDBC?

Vrundesha Joshi
Vrundesha Joshi
Published on 02-Apr-2019 13:03:37
The refreshRow() method of the ResultSet interface refreshes the current row with the most recent value in the database.rs.refreshRow()Assume we have a table named cricketers_data with 7 records as shown below:+----+------------+------------+---------------+----------------+-------------+ | ID | First_Name | Last_Name  | Year_Of_Birth | Place_Of_Birth | Country     | +----+------------+------------+---------------+----------------+-------------+ | 1  | ... Read More

How to move the pointer of a ResultSet to the default position using JDBC?

Vrundesha Joshi
Vrundesha Joshi
Published on 02-Apr-2019 12:54:08
The beofreFirst() method of the ResultSet interface moves the cursor/pointer to its default position i.e. before the first record.rs.beforeFirst();Assume we have a table named cricketers_data with 6 records as shown below:+----+------------+------------+---------------+----------------+-------------+ | ID | First_Name | Last_Name  | Year_Of_Birth | Place_Of_Birth | Country     | +----+------------+------------+---------------+----------------+-------------+ | 1 | ... Read More

How to move the result set pointer to required position?

Vrundesha Joshi
Vrundesha Joshi
Published on 02-Apr-2019 12:36:52
The absolute() method of the ResultSet interface accepts an integer value representing the index of a row and moves the ResultSet pointer of the current ResultSet object to the specified position.Assume we have a table named cricketers_data with 6 records as shown below:+------------+------------+---------------+----------------+-------------+ | First_Name | Last_Name  | Date_Of_Birth | ... Read More

How to create a table in JDBC using another table?

Vrundesha Joshi
Vrundesha Joshi
Published on 02-Apr-2019 12:27:13
You can create a table same as an existing table using the following syntax:CREATE TABLE new_table as SELECT * from old_table;Assume we have a table named dispatches with 5 records as shown below:+-------------+--------------+--------------+--------------+-------+----------------+ | ProductName | CustomerName | DispatchDate | DeliveryTime | Price | Location       | +-------------+--------------+--------------+--------------+-------+----------------+ ... Read More

How to create and release a save point in JDBC?

Vrundesha Joshi
Vrundesha Joshi
Published on 02-Apr-2019 12:00:14
When you set a save point you define a logical rollback point within a transaction. If an error occurs past a save point, you can use the rollback method to undo either all the changes or only the changes made after the save point.Savepoint interface gives you the additional transactional ... Read More

How to drop constraint on a column of a table in a database using JDBC API?

Vrundesha Joshi
Vrundesha Joshi
Published on 02-Apr-2019 09:32:10
You can drop a constraint on a column of a table using the ALTER TABLE command.SyntaxALTER TABLE table_name DROP CONSTRAINT MyUniqueConstraint;Assume we have a table named Dispatches in the database with 7 columns namely id, CustomerName, DispatchDate, DeliveryTime, Price and, Location with description as shown below:+--------------+--------------+------+-----+---------+-------+ | Field     ... Read More

How to add a primary key constraint to a column of a table in a database using JDBC API?

Vrundesha Joshi
Vrundesha Joshi
Published on 02-Apr-2019 09:14:48
You can add a primary key constraint to a column of a table using the ALTER TABLE command.SyntaxALTER TABLE table_name ADD CONSTRAINT MyPrimaryKey PRIMARY KEY (column1, column2...);Assume we have a table named Dispatches in the database with 7 columns namely id, CustomerName, DispatchDate, DeliveryTime, Price and, Location with description as ... Read More
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