Comment mettre à jour le contenu d'un ResultSet à l'aide d'un programme JDBC ?

Pour mettre à jour le contenu du ResultSet, vous devez créer une instruction en passant le type ResultSet actualisable, comme :

//Creating a Statement object
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);

Tout comme les méthodes getXXX() et setXXX(), l'interface ResultSet fournit également la méthode updateXXX() méthode pour mettre à jour le contenu d’une ligne dans le jeu de résultats.

Ces méthodes acceptent une valeur de chaîne représentant l'index ou l'étiquette de colonne de la ligne à mettre à jour.

Veuillez noter que la table doit avoir une clé primaire si vous devez mettre à jour le contenu du ResultSet.

Exemple

Supposons que nous ayons une table appelée Employés contenant 5 enregistrements, comme indiqué ci-dessous :

+----+---------+--------+----------------+
| Id | Name    | Salary | Location       |
+----+---------+--------+----------------+
|  1 | Amit    | 3000   | Hyderabad      |
|  2 | Kalyan  | 4000   | Vishakhapatnam |
|  3 | Renuka  | 6000   | Delhi          |
|  4 | Archana | 9000   | Mumbai         |
|  5 | Sumith  | 11000  | Hyderabad      |
+----+---------+--------+----------------+

L'exemple suivant montre comment mettre à jour le contenu de l'ensemble de résultats :

import java.sql.*;
public class ResultSetExample {
   public static void main(String[] args) throws Exception {
      //Registering the Driver
      DriverManager.registerDriver(new com.mysql.jdbc.Driver());
      //Getting the connection
      String mysqlUrl = "jdbc:mysql://localhost/TestDB";
      Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
      System.out.println("Connection established......");
      //Creating a Statement object
      Statement stmt = con.createStatement(
      ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
      //Retrieving the data
      ResultSet rs = stmt.executeQuery("select * from Employees");
      //Printing the contents of the table
      System.out.println("Contents of the table: ");
      printRs(rs);
      //Moving the pointer to the starting point in the ResultSet
      rs.beforeFirst();
      //Updating the salary of each employee by 5000
      while(rs.next()){
         //Retrieve by column name
         int newSal = rs.getInt("Salary") + 5000;
         rs.updateInt( "Salary", newSal );
         rs.updateRow();
      }
      System.out.println("Contents of the ResultSet after increasing salaries");
      printRs(rs);
      // Set position to second record first
      rs.beforeFirst();
      rs.absolute(2);
      System.out.println("Record we need to delete: ");
      System.out.print("ID: " + rs.getInt("id"));
      System.out.print(", Salary: " + rs.getInt("Salary"));
      System.out.print(", Name: " + rs.getString("Name"));
      System.out.println(", Location: " + rs.getString("Location"));
      System.out.println(" ");
      //Deleting the row
      rs.deleteRow();
      System.out.println("Contents of the ResultSet after deleting one records...");
      printRs(rs);
      System.out.println("Goodbye!");
   }
   public static void printRs(ResultSet rs) throws SQLException{
      //Ensure we start with first row
      rs.beforeFirst();
      while(rs.next()){
         System.out.print("ID: " + rs.getInt("id"));
         System.out.print(", Salary: " + rs.getInt("Salary"));
         System.out.print(", Name: " + rs.getString("Name"));
         System.out.println(", Location: " + rs.getString("Location"));
      }
      System.out.println();
   }
}

Output

Connection established......
Contents of the table:
ID: 1, Salary: 3000, Name: Amit, Location: Hyderabad
ID: 2, Salary: 4000, Name: Kalyan, Location: Vishakhapatnam
ID: 3, Salary: 6000, Name: Renuka, Location: Delhi
ID: 4, Salary: 9000, Name: Archana, Location: Mumbai
ID: 5, Salary: 11000, Name: Sumith, Location: Hyderabad
Conetnets of the resultset after increaing salaries
ID: 1, Salary: 8000, Name: Amit, Location: Hyderabad
ID: 2, Salary: 9000, Name: Kalyan, Location: Vishakhapatnam
ID: 3, Salary: 11000, Name: Renuka, Location: Delhi
ID: 4, Salary: 14000, Name: Archana, Location: Mumbai
ID: 5, Salary: 16000, Name: Sumith, Location: Hyderabad
Record we need to delete:
ID: 2, Salary: 9000, Name: Kalyan, Location: Vishakhapatnam
Contents of the resultset after deleting one records...
ID: 1, Salary: 8000, Name: Amit, Location: Hyderabad
ID: 3, Salary: 11000, Name: Renuka, Location: Delhi
ID: 4, Salary: 14000, Name: Archana, Location: Mumbai
ID: 5, Salary: 16000, Name: Sumith, Location: Hyderabad
Goodbye!

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