Setting Up Multiple Data Sources (MDS) in VDM

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Article Goal

This guide explains how to set up Multiple Data Source (MDS) functionality in VDM by configuring a local SQL Server Express instance to unify and manage data across multiple databases.

What is MDS and Why Is It Needed?

VDM supports building Views that pull from multiple databases—referred to as Multiple Data Sources (MDS).

However, this requires additional configuration because:

• Data from different sources must be combined and processed centrally.

• VDM uses a local SQL Server Express database to temporarily house and unify the results.

Note: You must configure this SQL Express instance before creating or running any MDS-enabled views.

Install SQL Server Express

• Click Download to get Microsoft SQL Server 2025 Express.
• Complete the install steps for a "Basic" installation and accept the defaults.

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Create a New SQL Connection in VDM
 

• Open VDM

• Click Database from the top ribbon.

• Select New to create a new connection profile.

• Choose Microsoft SQL Server as the database type.

• Enter the Server (Workstation name) and Instance (SQLExpress).

• Enable Trusted Connection and Test the connection.

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Set the MDS SQL Database in Settings

• Navigate to Settings in VDM

• Locate the MDS SQL Database setting

• Select the newly created SQL connection profile from the dropdown list.

This step tells VDM which database to use as the temporary staging ground for combining results across multiple sources.

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