一旦您建立了語句對象,您可以使用Statement介面的execute()、executeUpdate()和executeQuery()方法之一來執行它。
execute()方法:該方法用於執行SQL DDL語句,它會傳回一個布林值,指定是否可以檢索ResultSet物件。
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); } }
Connection established...... false
executeUpdate(): 這個方法用來執行插入、更新、刪除等語句。它傳回一個整數值,表示受影響的行數。
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); } }
Connection established...... Rows inserted: 4
executeQuery():此方法用於執行傳回表格資料的語句(例如 select)。它傳回 ResultSet 類別的物件。
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(); } } }
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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