CREATE MESSAGE DEFINITION

Synopsis

CREATE [ OR MODIFY ] MESSAGE DEFINITION module.Name
    [ FOLDER 'folder_path' ]
    FOR module.Entity [ AS 'ExposedName' ] {
        AttributeName [ AS 'ExposedName' ] [ EXAMPLE 'text' ],
        module.Association/module.TargetEntity [ AS 'ExposedName' ] { ... },
        ...
    };

Mendix 11.15 and later. Below 11.15 the statement is refused; a message definition is then an entry of a message definition collection.

Description

Creates one message definition as its own document. Mendix 11.15 removed the message definition collection and stores each definition as a separate document. Studio Pro’s converter turns a collection into a folder with the collection’s name, holding one document per definition, so MD_Order with the definition OrderMessage becomes the folder MD_Order with the document OrderMessage in it.

The body is the collection’s DEFINITION entry: the same members, the same rules for attributes and associations, the same derived cardinality. See CREATE MESSAGE DEFINITION COLLECTION.

A mapping refers to the document by its two-part name:

mdl 1;
create message definition Sales.OrderMessage
  folder 'Messages/MD_Order'
  for Sales.Order as 'Orders' {
    OrderId,
    Total as 'GrandTotal',
    Sales.OrderLine_Order/Sales.OrderLine as 'Lines' { Sku, Quantity },
    Sales.Order_Customer/Sales.Customer { FirstName, Address example 'Kerstraat 5' }
  };

create import mapping Sales.IMM_Order
  with message definition Sales.OrderMessage
{
  create Sales.Order { OrderId = OrderId }
};

On 11.15 a mapping stores this reference in MessageDefinition2. A script written for an older version can still name a converted definition in three parts (Sales.MD_Order.OrderMessage): it resolves to the document in the folder MD_Order, and the mapping stores the two-part name.

Editing one without restating it

mdl 1;
alter message definition Sales.OrderMessage add member LastName in Customer;
alter message definition Sales.OrderMessage set member Total as 'GrandTotal';
alter message definition Sales.OrderMessage drop member Sku in Lines;

These are the collection’s member edits, addressed by the document’s two-part name.

Other statements

LIST MESSAGE DEFINITIONS [ IN module ];
DESCRIBE MESSAGE DEFINITION module.Name;
DROP MESSAGE DEFINITION [ IF EXISTS ] module.Name;

DESCRIBE writes this statement, so describe and exec round-trip. Dropping a definition that a mapping still uses is refused, and the mappings are named.

On 11.15 the collection statements (CREATE, ALTER, DESCRIBE and DROP MESSAGE DEFINITION COLLECTION) are refused with a hint to use this form, and LIST MESSAGE DEFINITION COLLECTIONS points to LIST MESSAGE DEFINITIONS.

See Also

CREATE MESSAGE DEFINITION COLLECTION, CREATE IMPORT MAPPING, CREATE EXPORT MAPPING