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IntStream 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 MoreCreate KeyValue Tuple from another collection in Java
To create KeyValue tuple from another collection, use the fromCollection() method. We will be creating the tuple from List collection. Let us first see what we need to work with JavaTuples. To work with KeyValue class in JavaTuples, you need to import the following package.import org.javatuples.KeyValue;Note: Download JavaTuples Jar library to run JavaTuples program. If you are using Eclipse IDE, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file. Refer the below guide for all the steps to run JavaTuples.Steps: How to run JavaTuples program in EclipseThe following ...
Read MoreIterate through KeyValue Tuple in Java
To iterate through the KeyValue tuple in Java, use the Iterable and loop it through using the for loop. Let us first see what we need to work with JavaTuples. To work with KeyValue class in JavaTuples, you need to import the following package:import org.javatuples.KeyValue;Note: Download JavaTuples Jar library to run JavaTuples program. If you are using Eclipse IDE, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file. Refer the below guide for all the steps to run JavaTuples:Steps: How to run JavaTuples program in EclipseThe following is ...
Read MoreHow to select or, shift to another database in MySQL using a JDBC API?
In general, You can change the current database in MySQL using the USE query.SyntaxUse DatabaseName;To change the current database using JDBC API you need to:Register the driver: 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 URL (String), username (String), password (String) as parameters to it.Create Statement: Create a Statement object using the createStatement() method of the Connection interface.Execute the Query: Execute the query using the execute() method of the Statement interface.ExampleFollowing JDBC ...
Read MoreHow to create a Stored procedure in a database using JDBC API?
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.To create a stored procedure in (MySQL) a database using JDBC API you need to:Register the driver: 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 ...
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 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 connect to Derby database using a JDBC program?
Apache Derby is a Relational Database Management System which is fully based on (written/implemented in) Java programming language. It is an open source database developed by Apache Software Foundation.Installing derby:Follow the steps given below to install derby:Visit the home page of Apache Derby home page https://db.apache.org/derby/. Click the Download tab.Select and click on the link of the latest version of Apache Derby.On clicking the selected link, you will be redirected to the Distributions page of apache derby. If you observe here, derby provides distributions namely, db-derby-bin, db-derbylib.zip, db-derby-lib-debug.zip, and db-derby-src.zip.Download the db-derby-bin folder. Copy its contents to a separate folder ...
Read MoreHow to convert a String into a Date object using JDBC API?
The valueOf() method of the Date object accepts a String value representing a Date in JDBC escape format i.e. yyyy-mm-dd and converts the given String value into java.sql.Date object.Date date = Date.valueOf(“date_string”);Assume we have created a table named employee_data with the description as shown below:+----------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------+--------------+------+-----+---------+-------+ | id | int(11) | YES | | NULL | | | Name | varchar(255) | YES | ...
Read MoreHow to add a new column to an existing table using JDBC API?
You can add a new column to a table using the ALTER TABLE command.SyntaxALTER TABLE table_name ADD column_name datatype;Assume we have a table named Sales in the database with 5 columns namely ProductName, CustomerName, DispatchDate, DeliveryTime, Price and, Location as shown below:+-------------+--------------+--------------+--------------+-------+----------------+ | ProductName | CustomerName | DispatchDate | DeliveryTime | Price | Location | +-------------+--------------+--------------+--------------+-------+----------------+ | Key-Board | Raja | 2019-09-01 | 08:51:36 | 7000 | Hyderabad | | Earphones | Roja | 2019-05-01 | 05:54:28 | 2000 ...
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