Leverage the Looping Shape in an Orchestration

So I was tasked with generating a new BizTalk project that would update an email field in a SQL database. Great I thought, a simple orchestration with straight forward mapping ought to do the trick. And there I went, pointing and clicking away until I was thrown a curve by management. I was asked to leverage a stored procedure to update the field. Ordinarily, this isn't a problem, but we leverage a canonical schema from which all people records are derived. To update the stored procedure, I needed to devise a way of updating each record contained within in the canonical, one by one. What I was able to produce was an orchestration that enacted the Looping shape.

The way our canonical is formed, it contains an instance of an employee inside an employees node. The task was to extract each employee node, one by one, and push them out to the stored procedure via a send shape. Unfortunately, my stored procedure schema could only accommodate one record at a time, hence the loop shape.
First item of business was to determine how many records my canonical contained. Well, I needed a variable to hold this value, so I created one called recordCount. Now populating the recordCount required an xpath query to return the value. Now, xpath in BizTalk, can be a little cumbersome, but possible none the less. Taking my canonical schema I created this expression in a standard expression shape:

Now, the fun part. So I created a new Loop shape and entered

recordCount > 0

The next step entailed creating the single Employee message. To do this, you need a Construct Message shape. Within the Construct Message shape, you need to apply an Expression shape and Message Assignment shape. Obviously, the Message Assignment shape will handle the mapping of data from one message to another, but the Expression does the real work here. For this exercise, I created two temporary variables of type System.Xml.XmlDocument. Within my Expression shape, I was able to populate the temp variables with one record from my grand Employees canonical schema as such:

And of course, my Message assignment shape took the single Employee message and created a new message for the send port of the Update Email stored procedure.
Looping within an orchestration can be a clunky process, so I'd recommend you leave it as a last resort. But never the less, it beats writing hundreds of lines of c# code.

Happy Coding!