What is the difference between execute(), executeQuery() and executeUpdate() methods in JDBC?-Mysql Tutorial-php.cn

JDBC 中的execute()、executeQuery() 和executeUpdate() 方法有什么区别？

Once you create a statement object, you can execute it using one of the execute(), executeUpdate(), and executeQuery() methods of the Statement interface.

execute() method:This method is used to execute SQL DDL statements. It returns a Boolean value specifying whether the ResultSet object can be retrieved.

Example

import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.Statement; public class Example { public static void main(String args[]) throws SQLException { //Registering the Driver DriverManager.registerDriver(new com.mysql.jdbc.Driver()); //Getting the connection String mysqlUrl = "jdbc:mysql://localhost/sampleDB"; Connection con = DriverManager.getConnection(mysqlUrl, "root", "password"); System.out.println("Connection established......"); //Creating the Statement Statement stmt = con.createStatement(); //Executing the statement String createTable = "CREATE TABLE Employee( " + "Name VARCHAR(255), " + "Salary INT NOT NULL, " + "Location VARCHAR(255))"; boolean bool = stmt.execute(createTable); System.out.println(bool); } }

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Output

Connection established...... false

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executeUpdate():This method is used to execute insert, update, delete and other statements. It returns an integer value representing the number of rows affected.

Example

import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.Statement; public class ExecuteUpdateExample { public static void main(String args[]) throws SQLException { //Registering the Driver DriverManager.registerDriver(new com.mysql.jdbc.Driver()); //Getting the connection String mysqlUrl = "jdbc:mysql://localhost/sampleDB"; Connection con = DriverManager.getConnection(mysqlUrl, "root", "password"); System.out.println("Connection established......"); //Creating the Statement Statement stmt = con.createStatement(); String insertData = "INSERT INTO Employee(" + "Name, Salary, Location) VALUES " + "('Amit', 30000, 'Hyderabad'), " + "('Kalyan', 40000, 'Vishakhapatnam'), " + "('Renuka', 50000, 'Delhi'), " + "('Archana', 15000, 'Mumbai')"; int i = stmt.executeUpdate(insertData); System.out.println("Rows inserted: "+i); } }

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Output

Connection established...... Rows inserted: 4

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executeQuery():This method is used to execute statements that return table data (such as select). It returns an object of ResultSet class.

Example

import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class ExecuteQueryExample { public static void main(String args[]) throws SQLException { //Registering the Driver DriverManager.registerDriver(new com.mysql.jdbc.Driver()); //Getting the connection String mysqlUrl = "jdbc:mysql://localhost/sampleDB"; Connection con = DriverManager.getConnection(mysqlUrl, "root", "password"); System.out.println("Connection established......"); //Creating the Statement Statement stmt = con.createStatement(); //Retrieving data ResultSet rs = stmt.executeQuery("Select *from Employee"); while(rs.next()) { System.out.print("Name: "+rs.getString("Name")+", "); System.out.print("Salary: "+rs.getInt("Salary")+", "); System.out.print("City: "+rs.getString("Location")); System.out.println(); } } }

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Output

Connection established...... Name: Amit, Salary: 30000, City: Hyderabad Name: Kalyan, Salary: 40000, City: Vishakhapatnam Name: Renuka, Salary: 50000, City: Delhi Name: Archana, Salary: 15000, City: Mumbai

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