如何使用存储过程进行选择

Question

How can I retrieve (SELECT) all my data using Stored Procedure while using this Stored Procedure via Callable Statement? I created a sample project where I need to SELECT all the data from my table. First I used a Prepared Statement so I can insert data to the following textfields. Btw I'm using derby.

TABLE

CREATE TABLE SAMPLEONLY
(
FULLNAME VARCHAR(50),
ADDRESS VARCHAR(50)
)

GUI

CODES FOR INSERT

    private void addButtonActionPerformed(java.awt.event.ActionEvent evt) {                                          
    String addFullname = fullnameTf.getText();
    String addAddress = addressTf.getText();


    String insert = "INSERT INTO SAMPLEONLY (FULLNAME,ADDRESS) VALUES (?,?)";
    try (Connection myConn = DriverManager.getConnection(url, user, pass);
        PreparedStatement myPs = myConn.prepareStatement(insert);){

        myPs.setString(1, addFullname);
        myPs.setString(2, addAddress);

        myPs.executeUpdate();


    } catch (SQLException e) {
        e.printStackTrace();
    }
}

After inserting to the following textfields. I need to retrieve all my data using Stored Procedure. I created a stored procedure base on what I read on Derby Reference Manual. How can insert SELECT * FROM SAMPLEONLY in my Stored Procedure?

STORED PROCEDURE

CREATE PROCEDURE show_data(IN FULLNAME VARCHAR(50), IN ADDRESS VARCHAR(50))
PARAMETER STYLE JAVA
LANGUAGE JAVA
READS SQL DATA
EXTERNAL NAME 'Frame.searchButton'
//HOW CAN I INSERT HERE?

How can I insert the SELECT * FROM SAMPLEONLY here? I'm a little bit confused creating this stored procedure because this is my first time to use this. I named my class as Frame

CODE FOR SELECT

private void searchButtonActionPerformed(java.awt.event.ActionEvent evt) {                                             
    String seeachStoredProc = "{call show_data(?,?)}";

    try (Connection myConn = DriverManager.getConnection(url, user, pass);
         CallableStatement myCs = myConn.prepareCall(seeachStoredProc);)
        {

                //what goes here?

        } 
    catch (SQLException e) 
    {
        e.printStackTrace();
    }
}

Any help will appreciate! Guide me if something wrong in my codes. Feel free to comment.

Answer 1

Please use below code

Stored procedure

CREATE PROCEDURE show_data(IN FULLNAME VARCHAR(50), IN ADDRESS VARCHAR(50))
PARAMETER STYLE JAVA
LANGUAGE JAVA
READS SQL DATA
EXTERNAL NAME 'Frame.searchButton'
BEGIN

INSERT INTO SAMPLEONLY("FULLNAME", "ADDRESS") 
  VALUES (FULLNAME , ADDRESS);  

  COMMIT;

END;

CODE FOR SELECT

private void searchButtonActionPerformed(java.awt.event.ActionEvent evt) {                                             
String seeachStoredProc = "{call show_data(?,?)}";

try (Connection myConn = DriverManager.getConnection(url, user, pass);
     CallableStatement myCs = myConn.prepareCall(seeachStoredProc);)
    {

        String addFullname = fullnameTf.getText();
            String addAddress = addressTf.getText();
        myCs .setInt(1, addFullname 
        myCs .setString(2, addAddress );            

        // execute store procedure
        myCs .executeUpdate();   

    } 
catch (SQLException e) 
{
    e.printStackTrace();
}
}

Answer 2

You could use something like the following:

CREATE PROCEDURE show_data(IN FULLNAME VARCHAR(50), IN ADDRESS VARCHAR(50))
PARAMETER STYLE JAVA
LANGUAGE JAVA
READS SQL DATA
DYNAMIC RESULT SETS 1
EXTERNAL NAME 'SomeClass.showData'

Inside the SomeClass class (or the forms class) add an static method called showData that has two string parameters

public class SomeClass{
  public static void showData(String fullname, String address, ResultSet[] data){
    Connection conn = ... //somehow create a connection to database
    PreparedStatement ps = conn.prepareStatement("SELECT * FROM SAMPLEONLY");
    data[0] = ps.executeQuery();
    conn.close();
  }
}

And inside your button

CallableStatement cs = conn.prepareCall("{ call showData(?, ?)}");
cs.setString(1, p1);
cs.setString(2, p2);
boolean hasResults = cs.execute();
if (hasResults) {
  ResultSet rs = cs.getResultSet();
  while (rs.next()) {
      // do stuff with selected data
  }
}

EDIT I've noticed that when you access to the connection in the stored procedure, you must use the connection string jdbc:default:connection So in the code above change the connection line

public class SomeClass{
  public static void showData(String fullname, String address, ResultSet[] data){
    Connection conn = DriverManager.getConnection("jdbc:default:connection");
    PreparedStatement ps = conn.prepareStatement("SELECT * FROM SAMPLEONLY");
    data[0] = ps.executeQuery();
    conn.close();
  }

In derby stored procedures you always return a result in form of another method parameter (in this case the ResultSet array). The NullException you're having is probably somewhere else }