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JDBC Select Records Example


This part gives a model on the most proficient method to choose/bring records from a table utilizing JDBC application. Prior to executing the accompanying model, ensure you have the accompanying set up −

  • To execute the accompanying precedent you can supplant the username and password with your real client name and password.

  • Your MySQL or whatever database you are utilizing is up and running.

Required Steps

The following advances are required to make another Database utilizing JDBC application −

  • Import the packages: Requires that you incorporate the bundles containing the JDBC classes required for database programming. Regularly, utilizing import java.sql.* will suffice.

  • Register the JDBC driver: Requires that you introduce a driver so you can open an interchanges channel with the database.

  • Open a connection: Requires utilizing the DriverManager.getConnection() strategy to make a Connection object, which speaks to a physical association with a database server.

  • Execute a query: Requires utilizing an object of sort Statement for building and presenting a SQL explanation to choose (for example bring ) records from a table.

  • Extract Data: Once SQL question is executed, you can bring records from the table.

  • Clean up the environment: Requires unequivocally shutting all database assets as opposed to depending on the JVM's rubbish collection.

Sample Code

Copy and glue the accompanying model in JDBCExample.java, assemble and keep running as pursues −

//STEP 1. Import required packages
import java.sql.*; 

public class JDBCExample { 

//JDBC driver name and database URL 

static final String JDBC_DRIVER = "com.mysql.jdbc.Driver"; 

static final String DB_URL = "jdbc:mysql://localhost/STUDENTS"; 

//Database credentials 

static final String USER = "username"; 

static final String PASS = "password"; 

public static void main(String[] args) { 

Connection conn = null; 

Statement stmt = null; 

try{ 

//STEP 2: Register JDBC driver 

Class.forName("com.mysql.jdbc.Driver"); 

//STEP 3: Open a connection 

System.out.println("Connecting to a chose database..."); 

conn = DriverManager.getConnection(DB_URL, USER, PASS); 

System.out.println("Connected database successfully..."); 

//STEP 4: Execute a query 

System.out.println("Creating statement..."); 

stmt = conn.createStatement();
String sql = "SELECT id, first, last, age FROM Registration"; 

ResultSet rs = stmt.executeQuery(sql); 

//STEP 5: Extract information from result set 

while(rs.next()){ 

//Retrieve by section name 

int id = rs.getInt("id"); 

int age = rs.getInt("age"); 

String first = rs.getString("first"); 

String last = rs.getString("last"); 

//Display values 

System.out.print("ID: " + id); 

System.out.print(", Age: " + age); 

System.out.print(", First: " + first); 

System.out.println(", Last: " + last); 

} 

rs.close(); 

}catch(SQLException se){ 

//Handle mistakes for JDBC 

se.printStackTrace(); 

}catch(Exception e){ 

//Handle mistakes for Class.forName 

e.printStackTrace(); 

}finally{ 

//at long last square used to close resources 

try{ 

if(stmt!=null) 

conn.close(); 

}catch(SQLException se){ 

}//do nothing 

try{ 

if(conn!=null) 

conn.close(); 

}catch(SQLException se){ 

se.printStackTrace(); 

}//end at long last try 

}//end try 

System.out.println("Goodbye!"); 

}//end main 

}//end JDBCExample

Now, let us accumulate the above precedent as pursues −

C:\>javac JDBCExample.java 

C:\>

When you run JDBCExample, it creates the accompanying outcome −

C:\>java JDBCExample 

Connecting to a chose database... 

Connected database successfully... 

Creating statement... 

ID: 100, Age: 18, First: Zara, Last: Ali 

ID: 101, Age: 25, First: Mahnaz, Last: Fatma 

ID: 102, Age: 30, First: Zaid, Last: Khan 

ID: 103, Age: 







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