Taming the Tide of Change: Version Control Strategies for Your SQL Server Database

Version control systems (VCS) like Subversion (SVN) are essential for managing changes to code. They track modifications, allowing you to revert to previous versions if needed. This is just as crucial for databases as it is for code.

There are two main approaches to version control for SQL Server databases:

1. Scripting Database Schema Changes: This involves creating scripts that define the structure of your database (tables, views, stored procedures, etc.). Every time you modify the schema, you update the script. These scripts are then stored under version control using SVN.

• Benefits: Simple to implement, easy to see changes, and allows reverting to prior versions of the schema.
• Drawbacks: Doesn't track data changes, requires writing and maintaining scripts for all modifications.

1. Third-party Tools: Several tools like VersionSQL integrate with SQL Server and SVN. These tools allow you to directly connect your database to the SVN repository. You can then commit changes directly from SQL Server Management Studio.

• Benefits: Easier workflow, can potentially manage data changes (depending on the tool), automates some version control tasks.
• Drawbacks: May require additional software purchases, introduces a layer of complexity.

Using SVN for Database Schema Scripting

Here's a general workflow for using SVN to track schema changes:

Things to Consider

• Data Versioning: SVN primarily tracks schema changes, not data modifications. For data versioning, explore Slowly Changing Dimension (SCD) techniques or consider specialized database version control tools.
• Automation: While SVN offers manual version control, some third-party tools can automate deployment scripts based on your commits.

CREATE TABLE dbo.Users (
  UserID INT PRIMARY KEY IDENTITY,
  Username VARCHAR(50) NOT NULL UNIQUE,
  Email VARCHAR(100) NOT NULL UNIQUE,
  IsActive BIT DEFAULT 1
);

This script defines a simple "Users" table. You would store this file in your SVN repository.

Modifying the Schema (add_password.sql):

Later, you might decide to add a password column. You would create a new script:

ALTER TABLE dbo.Users
ADD Password NVARCHAR(MAX);

This script modifies the existing "Users" table. You would commit this new script to SVN along with a message indicating the addition of the password column.

Remember: These scripts don't directly interact with SVN. They represent the actual database schema changes that you would track using SVN's version control functionalities.

Additional Notes:

• Script naming conventions can help with organization. Consider prefixes like "create_", "alter_", or "drop_" for different actions.
• Version numbering in filenames (e.g., 001_create_users.sql) can be helpful for tracking the order of schema changes.

These tools integrate directly with SQL Server and offer a more streamlined workflow compared to manual script management. Here are a few popular options:

• VersionSQL: Integrates with popular VCS like SVN, Git, and TFS. Allows versioning of schema changes, data, and user objects.
• ApexSQL Source Control: Similar to VersionSQL, offers integration with various VCS and manages schema, data, and permissions.
• Flyway: Focuses on schema migration and deployment. Tracks changes through versioned migration scripts and automates deployments.
• DBmaestro: Comprehensive database lifecycle management tool. Provides version control, deployment automation, and impact analysis.

These tools often offer additional features like:

• Visual Schema Comparison: Easily compare schema changes between versions.
• Deployment Automation: Automate deployments based on version control commits.
• Data Versioning (limited): Some tools can manage specific data changes, but this functionality might be limited compared to dedicated data warehousing solutions.

Microsoft SQL Server Data Tools (SSDT):

This is a free, built-in tool within Visual Studio for working with SQL Server databases. While not a full-fledged version control system, SSDT offers features useful for version control:

• Database Projects: Create projects containing database objects (tables, views, etc.) defined as scripts.
• Source Control Integration: Integrate your project with a VCS like Git for version control of the scripts.
• Deployment: Generate deployment scripts (DACPAC packages) for deploying schema changes to different environments.

Choosing the Right Method

The best method depends on your specific needs and preferences. Here's a quick guide:

• Simple Schema Changes, Basic Needs: Scripting with SVN might suffice for small projects with infrequent schema changes.
• Streamlined Workflow, Additional Features: Consider third-party tools for a more user-friendly experience and potentially data versioning capabilities.
• Integration with Visual Studio: If you already use Visual Studio, SSDT could be a good option for basic version control and deployment.