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Please explain me Jdbc concept through small program. Anyone ?
9 Antworten
+ 2
STEP 1. Import required packages
import java.sql.*;
public class FirstExample {
// JDBC driver name and database URL
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost/EMP";
// 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 database...");
conn = DriverManager.getConnection(DB_URL,USER,PASS);
//STEP 4: Execute a query
System.out.println("Creating statement...");
stmt = conn.createStatement();
String sql;
sql = "SELECT id, first, last, age FROM Employees";
ResultSet rs = stmt.executeQuery(sql);
//STEP 5: Extract data from result set
while(rs.next()){
//Retrieve by column 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);
}
//STEP 6: Clean-up environment
rs.close();
stmt.close();
conn.close();
}catch(SQLException se){
//Handle errors for JDBC
se.printStackTrace();
}catch(Exception e){
//Handle errors for Class.forName
e.printStackTrace();
}finally{
//finally block used to close resources
try{
if(stmt!=null)
stmt.close();
}catch(SQLException se2){
}// nothing we can do
try{
if(conn!=null)
conn.close();
}catch(SQLException se){
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Now I get the concept. Thanks! That was very helpful.
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load the driver do step2 is not necessairy and this code for mysql sgbdr
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how do I get the information about driver for different database ?
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jdbc api java for connect to database he have a class Connection for open new connection to a database. Interface Statement for prepare and sand request sql . Class ResultSet use only for request of read. this class have function next() for past a next record type return is boolean and accessor getObject(num) for Object and getString(num) for String etc
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how do I know the name of the driver and its URL ? that's what I meant actually.
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if you use netBeans as IDE a driver for mysql is preinstaled just url for open new connection:
Connection c;
c= new Connection("jdbc:mysql://localhost/nameOfYouDatabase","root","");
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i hope that my example helpful you
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@ghost men, indeed. it was very helpful. Thanks.