Get int value from ResultSet : Query ResultSet « Database « Java Tutorial






import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class Main {
  public static void main(String[] args) throws Exception {
    Connection conn = getConnection();
    Statement st = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
        ResultSet.CONCUR_UPDATABLE);

    st.executeUpdate("create table survey (id int,name varchar(30));");
    st.executeUpdate("insert into survey (id,name ) values (1,'nameValue')");
    st.executeUpdate("insert into survey (id,name ) values (2,null)");
    st = conn.createStatement();
    ResultSet rs = st.executeQuery("SELECT * FROM survey");

    // extract data from the ResultSet
    while (rs.next()) {
      int id = rs.getInt(1);
      System.out.println("id=" + id);
      String name = rs.getString(2);
      System.out.println("name=" + name);
      if (rs.wasNull()) {
        System.out.println("name is null");
      } else {
        System.out.println("name is not null");
      }
      System.out.println("---------------");
    }
    rs.close();
    st.close();
    conn.close();

  }

  private static Connection getConnection() throws Exception {
    Class.forName("org.hsqldb.jdbcDriver");
    String url = "jdbc:hsqldb:mem:data/tutorial";

    return DriverManager.getConnection(url, "sa", "");
  }
}








20.6.Query ResultSet
20.6.1.ResultSet's Methods to Access Columns by Index
20.6.2.ResultSet's Methods to Access Columns by Name
20.6.3.ResultSet: A SQL query returns a ResultSet containing the requested data
20.6.4.Get Data from a ResultSet
20.6.5.Retrieving the Value of a Column Using the Index Number
20.6.6.Retrieving the Value of a Column Using the Column Name
20.6.7.Selecting all rows from a table and creates a result set:
20.6.8.If you Do Not Know the Name, Position, and Type of Each Column, how to get value from ResultSet
20.6.9.Determine If a Fetched Value Is NULL
20.6.10.Get int value from ResultSet
20.6.11.Get the Number of Rows in a Database Table
20.6.12.Limit the Number of Rows Returned from a SQL Query
20.6.13.Checking for a Warning Using a ResultSet Object
20.6.14.Convert a ResultSet to XML
20.6.15.Converting types: DATE to String