Resolving Missing Customer Data in `dimCustomer` Table

Issue: Missing Customer Data in dimCustomer Table

Analysis

Your issue seems to be related to the dimCustomer table not being updated with new customer entries present in the Sales fact table. This discrepancy leads to blank rows in the relationship window due to unmatched customer numbers.

Root Causes

1. Data Refresh Issue: The dimCustomer table isn't getting updated during your daily refresh process.
2. Data Source Mismatch: New customers might be added to the Sales fact table but not reflected in the dimCustomer source.
3. ETL Process Gaps: There might be gaps in your Extract, Transform, Load (ETL) process preventing new entries from reaching the dimCustomer table.

Steps to Diagnose

1. Verify Data Source:

   • Ensure the source file or database for dimCustomer includes the new customers.

2. Check Refresh Process:

   • Confirm whether the dimCustomer table's data source is included in your daily refresh schedule.

3. ETL Pipeline Review:

   • Inspect the ETL process for dimCustomer updates. Ensure new customers are captured and loaded properly.

Solutions

1. Incorporate dimCustomer Update in Refresh Process:

   • Ensure both Sales and dimCustomer tables are refreshed daily.

2. Update ETL Process:

   • Modify your ETL process to include new customers consistently.

3. Data Validation:

   • Add a validation step to check if all customer IDs in Sales exist in dimCustomer.

Power Query Example (M Language)

To ensure dimCustomer table is always refreshed, use Power Query (M language) to ensure completeness.

let
    // Source: Load the latest data for dimCustomer
    Source = Excel.Workbook(File.Contents("path_to_dimCustomer.xlsx"), null, true),

    // Assuming Sheet1 contains your dimension data
    dimCustomer = Source{[Name="Sheet1"]}[Content],

    // Perform necessary transformations here
    TransformedData = Table.TransformColumnTypes(dimCustomer, {{"CustomerID", type text}})
in
    TransformedData

SQL Example

If using a SQL database, ensure you are querying the latest dataset.

-- Query to retrieve latest customer data
SELECT CustomerID, CustomerName, OtherColumns
FROM dimCustomer

Best Practices

1. Consistent Refresh Schedule:

   • Ensure all related tables are refreshed simultaneously.

2. ETL Monitoring:

   • Implement monitoring and logging in your ETL processes for early detection of issues.

3. Data Validation Routines:

   • Establish routines to validate data integrity across related tables.

Recommendations for Further Learning

• Enterprise DNA Platform: Explore advanced courses for data modeling and Power Query to refine your approach to handling ETL processes and data refresh cycles.

By addressing the root cause and ensuring proper ETL processes, you will likely resolve the issue of missing customers in the dimCustomer table.