Question

Im doing a college assignment that requires me to create a PLSQL procedure that where the user can add a new customer order containing a number of items and the quantity for each item. I came up with the following that would ask the user to input a number of items to be added to the order and would then use a loop to ask for specific details such as product no and quantity. Im having problems with the user input at runtime though… When compiling the code it asks for the product code and quantity and wont ask again at runtime instead it saves the values given earlier at compile…

CREATE OR REPLACE 
PROCEDURE Add_Order (Item_amount IN NUMBER, CustNo IN NUMBER) AS

    ItemNo NUMBER; 
    var_Quantity NUMBER;
    var_PONo  NUMBER;  

    BEGIN  

      IF Item_amount BETWEEN 2 AND 9 THEN

        SELECT seq_PONo.NEXTVAL INTO var_PONo from dual;

    INSERT INTO PurchaseOrder_tab
         SELECT  var_PONo, REF(C),
                 SYSDATE,
                 ItemList_tab()
          FROM   Customer_tab C
          WHERE  C.CustNo = CustNo;

    FOR i IN 1..Item_amount LOOP
        DBMS_OUTPUT.PUT_LINE('INSIDE LOOP');
        ItemNo := &Enter_ProdCode;
        var_Quantity := &Quantity_Amount;

        INSERT INTO TABLE (
        SELECT  P.ItemList
          FROM  PurchaseOrder_tab P
         WHERE  P.PONo = var_PONo
        )

        SELECT   seq_ItemNo.nextval, REF(Pr), var_Quantity
          FROM   Products_tab Pr
         WHERE   Pr.ProductCode = ItemNo ;

        DBMS_OUTPUT.PUT_LINE('Added '||var_Quantity ||' items of '||ItemNo||' to order No: '||var_PONo);


              END LOOP;    

      ELSE

    DBMS_OUTPUT.PUT_LINE('Amount of items entered onto an order must be between 2 - 9. Please try again with correct amount.');

      END IF;

    EXCEPTION


    WHEN OTHERS THEN DBMS_OUTPUT.PUT_LINE('Operation failed '||'SQLCODE: '||SQLCODE);
    DBMS_OUTPUT.PUT_LINE('SQL Error Message '||SQLERRM);
    ROLLBACK;   
    END;
    /

Answer 1

Short answer: you can’t. PL/SQL is executed inside the database engine, and the database engine has no access to the terminal window (or database tool) you are using to start the procedure.

The code in your quesion seems to partially work, because it asks for input once, but what really happens is that: the tool (SQL*Plus, SQL Developer or whatever) parses over the PL/SQL block and sees the &-Signs, so it asks what to replace them with. Once the input is given, the PL/SQL-Block – including the entered values – is given to the database for execution.

Since you can’t do that in PL/SQL, better create a front-end program first that collects the values, then sends them to the database.