Creating Data for a Child Class From Another Data Class Using an Operation

This document provides information on how to use an operation to create data for a child data class from a different data class (not necessarily its parent class).

The process described below demonstrates how to add data to the child class (MYCLASS1.CL1) of a data class (MYCLASS1) from a different data class (MYCLASS2). This is done by adding a script that will create an operation on (MYCLASS1), called from (MYCLASS2):

1. Open your data class (MYCLASS1).
2. In the Methods block of th Methods tab:
   
   1. Enter a new method code (MYMETH1) in the Code field.
   2. Enter a description for the method in the Description field.
   3. Select an appropriate return type in the Return type field.
   4. Select the Operation check box. It will automatically generate the keys in the Keys block.
3. In the Parameter definitions block, enter parameters (MYPARAM1) that need to be passed.
4. In the Scripts block of the General tab:
   1. Select the appropriate type for your script in the Type field.
   2. Accept the default code displayed in the Scripts field. It is automatically generated using the class code and the script type. You can also manually enter a unique code for your script.
   3. Accept the numeric value displayed in the Running order field. It is automatically generated to control the order in which the "$PROPERTIES" and "$METHODS" labels are called in the event. You can also manually enter the running order code for your script.
5. Click the Actions button of your script, and click Processing editor. Enter the source code below.
   Note: This example uses the key passed in the Keys block of the Methods tab to read the current context from "MYCLASS1", and then update the property (PROP1) using parameter "MYPARAM1" which is passed to it.
   

   $Structure MYCLASS1
   ##########################################
   #             METHODS                    #
   ##########################################
   $METHODS
     Case CURPTH
       When ""
           Case ACTION
              When "MYMETHOD" Gosub MYMETHOD  # Update MYPROP1 method 
           Endcase  
     Endcase
   Return
   # Update MYPROP1 using MYPRAM1 which is passed
   # KEY1 and MYPARAM1 are passed and used in this operation
   $MYMETHOD
      Local Integer NEWLINE
       # Use standard method CRUD to read MYCLASS1
       ASTATUS=fmet this.AREAD(MYCLASS1)
       If ASTATUS<>[V]CST_AOK
         ARET_VALUE= CST_AFALSE
         Return
       Else
         ARET_VALUE= CST_ATRUE
         # create a new line for MYCLASS1.CL1 at last position
         NEWLINE=fmet this.ADDLINE("CL1",[V]CST_ALASTPOS)
         If NEWLINE=[V]CST_ANOTDEFINED # check status after creating line
           ARET_VALUE = CST_AFALSE
         Endif
         If ARET_VALUE = CST_ATRUE
           # update CL1 with values passed 
           this.CL1(NEWLINE).MYPROP1 = MYPARAM1
           ASTATUS=fmet this.AUPDATE
           If ASTATUS<>[V]CST_AOK
             ARET_VALUE= CST_AFALSE
           Endif
         Endif
       Endif
   Return

6. Once the operation has been created, call it from data class "MYCLASS2", or from any other data class.
   Enter code similar to the following. It calls "MYMETHOD" which was defined above.
   

   ##############################################
   #  Data Class -  MYCLASS2                    #
   ##############################################
   ##############################################
   #                METHODS                     #
   ##############################################
   $METHODS
     Case CURPRO
       When ""
         Case ACTION
           When "AINSERT_AFTER" : Gosub AINSERT_AFTER
         Endcase
     Endcase
   Return
   # Action After insert
   $AINSERT_AFTER
       # Declaration new instance of MYCLASS2 data class
       Local Instance MYCLASS Using C_MYCLASS2
       MYCLASS = NewInstance C_MYCLASS2 AllocGroup Null
       ASTATUS=fmet MYCLASS.MYMETHOD(KEYID,MYPARM1)
       If ASTATUS<>[V]CST_ATRUE
         ASTATUS = fmet THIS.ASETERROR ("", "Not updated.", [V]CST_AERROR)    
       Endif
       # Free instances
       FreeGroup MYCLASS
   Return

7. Save your script.
8. Save and validate your data class.