Understand DML Blocks

Main Blocks are small processing engines that generate new data by using (or not using) incoming data. Incoming data is supplied to Main Blocks through their inputs and the resulting generated data is transferred outside Main Blocks through their outputs. You can define as many inputs and outputs as needed, each with a different name.

Before processing a Main Block, the integration engine server feeds all inputs with the appropriate data. The key concept here is that input data is made available by a process that is exterior to the Main Block. This means that when defining the internal processes of the Main Block you do not need to issue instructions for data collection because this is already done. You only need to define which parts of the data have to be picked-up for the generation of output.

Main Blocks are software programs that map data, therefore, you have to provide instructions to tell them how to perform this action. This can be done in three ways, depending on the type of the Main Block:

typeMain Block Instructions are supplied using

WS Block

Web-Service channel

DB Block

DB channel

SAP Block

SAP channel

DML Block

DML expressions

Because this guide is dedicated to DML, you are concerned here with DML Blocks only.

DML Blocks can generate data to multiple outputs. Each output carries data using a certain format defined in the Business Document attached to this output. Instructions are structured in DML Blocks around the format of the output. For each output Business Document, you define a set of rules on how to build this output Business Document. Such a set of rules is called a Map.

The following graphic illustrates a Map:

 

As shown in the preceding graphic, Maps are composed of individual or elementary rules, each rule attached to a specific node of the output Business Document. Each of these individual rules is a DML expression that generates the value of the node to which it is bound. Such expressions might pick up data from the available inputs, or ignore the input data and use constants to generate output values.

After you have defined a set of Maps, your DML Block knows how to generate data suitable for a specific Business Document. You then need to specify which Maps might be used to produce documents for this or that output. You make this specification for the DML Block by using additional objects.

In a DML Block you define how data is processed. For this you have some objects available which you can combine.

For example such objects are Conditions like Decision or Switch, Actions like Map, Parse or Route to or Advanced objects like Loop, While, Exit or Set.

The following graphic illustrates how such a DML Block is displayed in Axway Mapping Services:

DML Block

As you can see, there are some combined objects. Each object invokes a certain action which can be:

  • making decisions (If/Then/Else or Switch/Case steps)
  • repeating an action (Loop and While steps)
  • transferring data from the input structure to the output structure (Output steps)
  • activating one of the Maps (Map steps)

A complete description of what is possible is beyond the scope of this guide. Refer to the Axway, Axway B2Bi and Axway Mapping Services online help for more details.

Related topics

Introducing DML

Data mapping in an integration engine

Approving input data with Validation Rules

What is DML?

FoodBroker project: Doing the first steps

Creating a Business Document for the customer request

Creating a Business Document for the partner

Creating a Business Document for billing and delivery

Creating a Business Document for partner rates

Building the Flow

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