Data Warehousing and Dynamics 365 for Finance and Operation - A Few Issues to Consider I

Data Warehousing Series

Introduction

Besides the fact that data professionals don't have direct access to D365 F&O production environments (direct access is available only to sandboxes), which was from the beginning an important constraint imposed by the architecture, there are a few more challenges that need to be addressed when working with the data.

Case Sensitiveness

SQL Server is not case sensitive, therefore, depending on the channel though which the data came, values appear either in upper or lower case, respectively a mixture of both. Even if this isn't an issue in D365, it can become an issue when the data leave the environment. E.g., PowerQuery is case sensitive (while DAX is case insensitive), thus, if a field containing a mix of values participate in a join or aggregation, this will result in unexpected behavior (e.g., duplicates, records ignored). It's primarily the case of the Company (aka DataAreaId) field available in most of the important tables.

The ideal solution would be to make sure that the values are correct by design, however this can't be always enforced. Otherwise, when using the data outside of D365 F&O the solution would be to transform all the values in upper case (or lower case). However, also this step might occur too late. E.g., when the data are exported to the Azure Data Lake in parquet file format.

Unique Keys

A unique record in D365 F&O was in earlier versions usually identified by the RecId and DataAreaId, while later the Partition field was added. This means that most of the joins will need to consider all 3 columns, which adds some overhead. In some environments there's only a Partition defined (and thus the field can be ignored), however this is not a warranty. 

As long developers use SQL there's no issue of using multiple fields in JOINs, though in PowerQuery there must be created a unique key based on the respective records so the JOINs are possible. Actually, also SQL-based JOINs would benefit if each record would be identified by one field.

Audit Metadata

Not all tables have fields that designate the date when a record was created or last modified, respectively the user who performed the respective action. The fields can be added manually when setting up the system, however that's seldom done. This makes it difficult to audit the records and sometimes it's a challenge also for reporting, respectively for troubleshooting the differences between DWH and source system. Fortunately, the Export to Data Lake adds a timestamp reflecting the time when the record was synchronized, though it can be used then only for the records synchronized after the first load. 

Tables vs. Entities

Data are modified in D365 F&O via a collection of entities, which are nothing but views that encapsulate the business logic, being based on the base tables or other views, respectively a combination of both. The Export to Data Lake (*) is based on the tables, while Link to Data Lake is based on data entities. 

Using the base tables means that the developer must reengineer the logic from the views. For some cases it might work to create the entities as views in the DWH environment though some features might not be supported. It's the case of serverless and dedicated SQL pools, that support only a subset from the features available under standard Azure SQL Server. 

The developer can try to replicate the logic from entities, considering only the logic needed by the business, especially when only a subset from the functionality available in the entity was used. The newly created views can become thus more readable and maintainable. On the other side, if the logic in entity changed, the changes need to be reflected also in the DWH views. 

Using the entity-based data makes sure that the data are consistent between environments. Unfortunately, Microsoft found out that isn't so easy to synchronize the data at entity level. Moreover, there are multiple entities based on the same table that reflect only a subset of the columns or rows. Thus, to cover all the fields from a base table, one might be forced to synchronize multiple views, leading thus to data duplication.  

In theory, both mechanisms can be used within the same environment, even if this approach is against the unique source of truth principle, when data are duplicated. 

Data Validation in the Data Lake

One scenario in which both sources are useful is when validating whether the synchronization mechanism worked as expected. Thus, one can compare the number of records and check whether there are differences that can't be mitigated. However, does it make sense to "duplicate" database objects only for this purpose?

Ideally, to validate whether a record was synchronized should be done in the source environment (e.g. via a timestamp). That's difficult to achieve, especially when there's no direct access to the source database (as is the case for Production databases). Fortunately, Dataverse provides this functionality, even if might not be bullet proof. 

In extremis, the most reliable approach is to copy the production environment on a sandbox and do a count of records for each table, using as baseline for comparison the time when the refresh occurred.

Base Enum Values

The list of values that don't have their own tables are managed within the application as Base Enums and, naturally, only the numeric values being saved to the database. Even if this is practical for the application, it's a nightmare for the people using the data exported from database as is needed to convert the codes to meaningful values. Some of the mappings between the codes and values are documented in two system tables, and even in old language-based documentation, though both sources are far from complete. As alternative, one can try to discover the values in the system. 

Unfortunately, the mappings need to be repeated when the Enum-based attributed is used in multiple places. One can reduce mapping's duplication by encapsulating the logic into a view (aka "base view") and reused accordingly (see the logic for TDM.vEcoResProduct).

Even if the values for many of the Enums are stored into the EnumValueTable table, Enum's name being available in EnumIdTable table, it's not a good idea to retrieve the values via a JOIN in the business logic. This would complicate the business logic unnecessarily. A CASE is more efficient even if occasionally more difficult to maintain. Unfortunately, there's no timestamp to identify which values were added lately.

Note:
(*) Existing customers have until 1-Nov-2024 to transition from Export to Data lake to Synapse link. Microsoft advises new customers to use Synapse Link.