BizTalk 2010 Recipes : Document Mapping - Using the Table Looping Functoid

1. Problem

You need to create a repeating structure in an output document with no equivalent repeating structure in an input document.

2. Solution

BizTalk Sever provides two functoids, the Table Looping functoid and the Table Extractor functoid, for creating a repeating node structure from a flattened input structure, from constant values, and from the output of other functoids. The Table Looping functoid is used to create a table of information based on inputs. The functoid will generate output for each row from this table. The Table Extractor functoid is used to direct data from each column in the table to a node in the destination document. Following are the basic steps for configuring these functoids.

3. How It Works

The Table Looping and Table Extractor functoids are used together. As an example, suppose that you have the sample input document shown in Listing 1.

Example 1. Flattened Input Structure

<AliasesFlat>
    <Names>
        <Alias1FirstName>John</Alias1FirstName>
        <Alias1LastName>Doe</Alias1LastName>
        <Alias2FirstName>Sam</Alias2FirstName>
        <Alias2LastName>Smith</Alias2LastName>
        <Alias3FirstName>James</Alias3FirstName>
        <Alias3LastName>Jones</Alias3LastName>
    </Names>
</AliasesFlat>

The goal is to use these two functoids to create an output document of the format shown in Listing 2.

Example 2. Repeating Nested Structure

<AliasesRepeating>
    <AliasNames>
        <FirstName>John</FirstName>
        <LastName>Doe</LastName>
    </AliasNames>
    <AliasNames>
        <FirstName>Sam</FirstName>
        <LastName>Smith</LastName>
    </AliasNames>
    <AliasNames>
        <FirstName>James</FirstName>
        <LastName>Jones</LastName>
    </AliasNames>
</AliasesRepeating>

Figure 1 shows the configuration for the input parameters for the Table Looping functoid. The first parameter is a reference to the node structure Names in the input schema. The second parameter is a constant value of 2 indicating there will be two columns in the table. The remaining parameters are the first and last name of each alias from the input document.

Figure 1. Table Looping input parameters

Figure 2 shows the completed Table Looping Configuration dialog box for the Table Looping functoid. It has been configured so that each row contains an alias first name in column 1 and an alias last name in column 2. There will be three rows in the table to process, one for each alias provided as input.

Figure 2. Table Looping Configuration dialog box

The output links from the Table Looping functoid are configured as follows:

• An output link to the AliasNames repeating node structure in the destination schema

• An output link to a Table Extractor functoid for processing first names (column 1) from the table

• An output link to a Table Extractor functoid for processing last names (column 2) from the table

Figure 3 shows the configuration for the Table Extractor functoid that will process column 1 from the table. The first parameter is a link from the Table Looping functoid, and the second parameter is a constant value of 1, which indicates it will process the first column from each row as it is processed.

Figure 3. Table Extractor functoid configuration for column 1

Figure 4 shows the configuration for the Table Extractor functoid that will process column 2 from the table. The first parameter is a link from the Table Looping functoid, and the second parameter is a constant value of 2, which indicates it will process the second column from each row as it is processed.

Figure 4. Table Extractor functoid configuration for column 2

Finally, each Table Extractor functoid must be linked to a node in the destination schema. The complete map is shown in Figure 5.

Figure 5. Final map for the Table Looping functoid example

Here is what the data table will look like when the map is processed:

Once the table is loaded, it will generate three sets of output: one set of output for each row in the table. This, in turn, will create three repetitions of the AliasNames node structure in the destination document: one for each row in the table. A repeating node structure has been created, even though one did not exist in the input document.