patterns-data-processing

Find it fast

sed -n '<from>,<to>p' SKILL.md one section rather than reading the file; ./mxcli syntax <topic> answers how do I write this for a fraction of either.

lines	section
27-106	Loop Patterns
107-199	Retrieve by Association
200-278	Aggregate Patterns
279-369	List Operations
370-413	Batch Processing
414-470	Data Transformation
471-504	Error Handling in Loops
505-512	Best Practices

Data Processing Patterns

Patterns for loops, aggregates, batch processing, and data transformation.

Loop Patterns

Basic Loop

mdl 1;
/**
 * Process all items in a list
 */
create microflow Module.ProcessItems (
  $Items: list of Module.Item
)
returns boolean
begin
  declare $ProcessedCount integer = 0;

  loop $item in $Items
  begin
    -- Process each item
    change $item (ProcessedDate = [%CurrentDateTime%]);
    commit $item;
    set $ProcessedCount = $ProcessedCount + 1;
  end loop;

  log info node 'Processing' 'Processed ' + $ProcessedCount + ' items';
  return true;
end;

Loop with Filtering

mdl 1;
/**
 * Process only active items
 */
create microflow Module.ProcessActiveItems (
  $Items: list of Module.Item
)
returns integer
begin
  declare $count integer = 0;

  loop $item in $Items
  begin
    if $item/IsActive then
      -- Process active item
      change $item (LastProcessed = [%CurrentDateTime%]);
      commit $item;
      set $count = $count + 1;
    end if;
  end loop;

  return $count;
end;

Loop with Accumulator

mdl 1;
/**
 * Calculate total value of all orders
 */
create microflow Module.CalculateOrderTotal (
  $Orders: list of Module.Order
)
returns decimal
begin
  declare $Total decimal = 0;

  loop $Order in $Orders
  begin
    set $Total = $Total + $Order/Amount;
  end loop;

  return $Total;
end;

Retrieve by Association

Use retrieve $list from $Parent/Module.AssociationName to retrieve related objects via association instead of a database XPath query. This is required for: