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Please explain me Jdbc concept through small program. Anyone ?

1st Jan 2017, 7:41 PM
Tamanna Sen
Tamanna Sen - avatar
9 odpowiedzi
+ 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){
1st Jan 2017, 8:05 PM
ghost men
ghost men - avatar
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Now I get the concept. Thanks! That was very helpful.
1st Jan 2017, 7:52 PM
Tamanna Sen
Tamanna Sen - avatar
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load the driver do step2 is not necessairy and this code for mysql sgbdr
1st Jan 2017, 7:59 PM
bouaabid
bouaabid - avatar
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how do I get the information about driver for different database ?
1st Jan 2017, 8:09 PM
Tamanna Sen
Tamanna Sen - avatar
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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
1st Jan 2017, 8:35 PM
bouaabid
bouaabid - avatar
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how do I know the name of the driver and its URL ? that's what I meant actually.
1st Jan 2017, 8:38 PM
Tamanna Sen
Tamanna Sen - avatar
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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","");
1st Jan 2017, 8:43 PM
bouaabid
bouaabid - avatar
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i hope that my example helpful you
1st Jan 2017, 9:37 PM
ghost men
ghost men - avatar
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@ghost men, indeed. it was very helpful. Thanks.
1st Jan 2017, 9:41 PM
Tamanna Sen
Tamanna Sen - avatar