PXAccumulator: To Implement a Custom Accumulator Attribute

The following activity will walk you through the process of implementing a custom accumulator attribute.

Story

In the Smart Fix company, the number of work orders assigned to each employee changes frequently. Users can assign work orders on both the Repair Work Orders (RS301000) form and the Assign Work Orders (RS501000) form. Multiple users may assign repair work orders to the same employee at the same time. These concurrent updates of a record trigger this error: Another process has updated the record.

To avoid this error, you’ll implement a custom attribute derived from the PXAccumulator attribute. The accumulator attribute modifies the SQL query and guarantees that concurrent updates of each record are handled smoothly. In this attribute, you’ll calculate the number of repair work orders assigned to each employee and enforce a maximum of 10.

Process Overview

You will create a custom accumulator attribute to calculate the numbers of assigned work orders for each employee during the assignment or completion of work orders.

You will also assign to the DAC the custom accumulator attribute that stores the field to be updated by the accumulator attribute.

System Preparation

Before you begin implementing a custom PXAccumulator attribute, do the following:

1. Prepare an MYOB Acumatica instance by performing the Test Instance for Customization: To Deploy an Instance with a Custom Form that Implements a Workflow prerequisite activity.

2. Create the database table and include the creation script in the customization project as follows:

   1. In SQL Server Management Studio, execute the T240_DatabaseTables.sql script to create the RSSVEmployeeWorkOrderQty database table.
   2. On the Database Scripts page of the Customization Project Editor, for the added table, do the following:
      1. On the page toolbar, click Add Custom Table Schema.
      2. In the dialog box that opens, select the table and click OK.
   3. Publish the project.
   Tip:

   For details on designing database tables for MYOB Acumatica, see Designing the Database Structure and DACs.

3. In the system, indicate the completion of all repair work orders that have the Assigned status on the Repair Work Orders (RS301000) form. Do the following for each of the repair work orders that has the Assigned status:

   1. Open the repair work order.
   2. Click Complete on the form toolbar.

   The RSSVEmployeeWorkOrderQty table will hold the number of repair work orders assigned to each employee. This table currently contains no data because you haven’t yet implemented the logic to update the data in the table. However, if any repair work orders assigned to employees, you need to complete them. As a result, none of the employees has repair work orders assigned and the table’s data correctly reflects the current state of the system.

Step 1: Creating a DAC (Self-Guided Exercise)

Step 2: Implementing the Accumulator Attribute

In this step, you’ll create the custom RSSVEmployeeWorkOrderQtyAccumulator accumulator attribute for the RSSVEmployeeWorkOrderQty DAC. For each employee, this attribute will compute the total of the number of assigned work orders and save the value in the RSSVEmployeeWorkOrderQty.NbrOfAssignedOrders field.

The attribute will be derived from the PXAccumulator system attribute. The base attribute can also be configured to calculate the values in the RSSVEmployeeWorkOrderQty.NbrOfAssignedOrders field. You will instead use the custom attribute because you need to specify a custom restriction for the number of work orders assigned to an employee—a maximum of 10.

To implement the custom accumulator attribute, do the following:

1. In the Messages.cs file, add the following constant with the message that’s displayed when the restriction specified in the accumulator attribute is violated.

           public const string ExceedingMaximumNumberOfAssignedWorkOrders =
               @"Updating the number of assigned work orders for the employee 
               will lead to exceeding of the maximum number of assigned work orders, 
               which is 10.";

2. In the RSSVEmployeeWorkOrderQty.cs file, define the RSSVEmployeeWorkOrderQtyAccumulator attribute as follows.

       public class RSSVEmployeeWorkOrderQtyAccumulator :
           PXAccumulatorAttribute
       {
           //Specify the single-record mode of update in the constructor.
           public RSSVEmployeeWorkOrderQtyAccumulator()
           {
               _SingleRecord = true;
           }
           //Override the PrepareInsert method.
           protected override bool PrepareInsert(PXCache sender, object row,
               PXAccumulatorCollection columns)
           {
               if (!base.PrepareInsert(sender, row, columns)) return false;
               RSSVEmployeeWorkOrderQty newQty = (RSSVEmployeeWorkOrderQty)row;
               if (newQty.NbrOfAssignedOrders != null)
               {
                   // Add the restriction for the value of 
                   // RSSVEmployeeWorkOrderQty.NbrOfAssignedOrders.
                   columns.AppendException(
                       Messages.ExceedingMaximumNumberOfAssignedWorkOrders,
                   new PXAccumulatorRestriction<
                       RSSVEmployeeWorkOrderQty.nbrOfAssignedOrders>(
                       PXComp.LE, 10));
               }
               // Update NbrOfAssignedOrders by using Summarize.
               columns.Update<RSSVEmployeeWorkOrderQty.nbrOfAssignedOrders>(
                   newQty.NbrOfAssignedOrders,
                   PXDataFieldAssign.AssignBehavior.Summarize);
               return true;
           }
       }

3. Add the RSSVEmployeeWorkOrderQtyAccumulator attribute to the RSSVEmployeeWorkOrderQty class, as shown below.

       [PXHidden]
       [RSSVEmployeeWorkOrderQtyAccumulator]
       public class RSSVEmployeeWorkOrderQty : PXBqlTable, IBqlTable
       {        ...
       }

   You have added the custom attribute directly to the RSSVEmployeeWorkOrderQty DAC because this class is updated only from code and not through the UI.

4. Build the project.