Hierarchical data formats play a major role in B2B data exchange. Most B2B data exchange takes place using hierarchical formats such as XML or EDI. Parsing, transforming, and building hierarchical documents is a complex process. Centerprise 6 Data Integrator brings major new functionality for working with hierarchical data formats.
Centerprise 6 features a large number of built-in transformations that enable users to develop the sophisticated flows needed for complex data integration. These transformations can be broadly classified into single transformations and set transformations.
Single transformations usually operate on a single record at a time and are used for looking up or computing values. Examples of single transformations include lookups, expressions, functions, and others.
Set transformations operate on a record set and may alter sequence and number of records in that set. Examples of set transformations include sort, filter, join, merge, normalize, denormalize, union, etc. Some transformations can be classified both as single and set, depending on whether they return a single record or multiple records. These transformations include lookups, subflows, and text parsers.
Generally, set transformations operate on the entire data set. For instance, a sort transformation sorts the entire data set before passing along records to the next object. Similarly, aggregate transformations use the entire data set to construct aggregated records.
This model, while perfectly suitable for flat structures, does not provide adequate semantics for dealing with hierarchical data.
Centerprise 6 now introduces the concept of Scoped Transformations, set transformations that can be limited to a specific node in the source tree, enabling the building and manipulation of complex hierarchical data structures.
A set transformation can be designated as a Scoped Transformation by creating a scope map between a source object node and the top node in the transformation. This is accomplished by pressing the Alt key while dragging a source node to the target. In the following example, the filter is a Scoped Transformation whose scope is Order node. This action attaches the result of a Filter to the Order node. For onward mapping, this action can be deemed as implicitly creating a Filter node collection inside the Order node.
Building a Simple Tree
We start with an example of using scoped transformations to build a simple sales order tree structure. While Centerprise offers many different ways of building tree structures, a Scoped Transformation will be used to accomplish the task in this instance.
This dataflow builds an order tree using Microsoft’s sample Northwind database. Even though you can build a tree in Centerprise using the Database Table Source and Tree Join Transformations, in this example we are using Scoped Transformations in order to illustrate their usefulness. The steps are described below:
Order – Database Table Source
The Order source retrieves data from the Order table in the database.
OrderDetail –Database Lookup
OrderDetail is a database lookup with the ‘Return All’ option selected. This means that the lookup will return all rows that match lookup keys. In this case, it will return all instances of OrderDetail for the specified Order object. This step creates a tree with the Order table containing a collection of OrderDetail data.
OrderTotals – Aggregate
OrderTotals is an aggregate transformation with no Group By fields defined. This step creates order level totals. The result is implicitly attached to the Order node as a single instance object.
OrderTree – Passthru
OrderTree is merely a passthru transformation that consolidates all the nodes in a unified tree object.
This simple scenario illustrates the power and versatility of the Centerprise 6 scoped transformation feature. Most Centerprise set transformations can be used as Scoped Transformations. These include filter, sort, distinct, lookups, aggregate, join, tree join, union, merge, normalize, denormalize, and others.