Imagine running a database comparison between environments, expecting to see every subtle difference, only to be surprised when synonyms seem to be overlooked. This scenario is more common than you might think, particularly when databases are migrated or compared across different servers or instances. The solution, thankfully, is straightforward and lies within understanding how SQL Compare, a powerful tool from Redgate, handles synonyms.
This article delves into why SQL Compare might initially miss differences in synonyms and, more importantly, how to configure it to ensure accurate and comprehensive comparisons, especially when dealing with synonyms. If you’re involved in database development or deployment, understanding this nuance can save you from potential headaches and ensure your database changes are accurately tracked and deployed.
The Scenario: Synonyms Pointing to Different Objects
Consider a common database development workflow. You might have a development environment with databases structured for feature-specific work, such as Sales_Feature and Finance_Feature. In Sales_Feature, you might create a synonym intended to point to an object in Finance_Feature. This setup works seamlessly within the development environment.
However, when moving to production, the database landscape shifts. You now have production databases like Sales and Finance. The synonym originally created in Sales_Feature needs to point to the Finance database in production, even though the underlying code might have originated from the development environment. While managing this development lifecycle presents its own challenges, let’s focus specifically on ensuring that SQL Compare accurately detects these synonym differences.
To illustrate, let’s create a practical example using two databases, SimpleTalk_1_Dev and SimpleTalk_5_Prod, on the same instance. In SimpleTalk_1_Dev, we create a synonym:
USE [SimpleTalk_1_Dev]
GO
CREATE SYNONYM dbo.MyTable FOR Compare1.dbo.MyTable
GONext, in SimpleTalk_5_Prod, we create a similar synonym but pointing to a different location, simulating a development-to-production difference:
USE [SimpleTalk_5_Prod]
GO
CREATE SYNONYM dbo.MyTable FOR Compare2.dbo.MyTable
GONow, if you were to run a comparison using SQL Compare between these two databases with default settings, you might be surprised by the result: no difference detected. Despite the synonyms clearly pointing to different objects, SQL Compare, by default, overlooks this distinction.
The Solution: Adjusting Project Options for Synonym Comparison
The reason SQL Compare initially misses these synonym differences lies in its default project settings. SQL Compare is designed to be intelligent about deployments across environments. It anticipates that database and server names might change between development and production, and by default, it assumes that you are primarily concerned with schema and object structure differences, rather than differences arising purely from environment-specific naming conventions in synonyms.
This behavior is controlled by a specific project option. To access it, open your SQL Compare project, click “Edit project,” and navigate to the “Options” tab. Scroll down, and you will find the option labeled “Ignore database and server name in synonyms.” This option is checked by default.
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By unchecking this “Ignore database and server name in synonyms” option and re-running the comparison between SimpleTalk_1_Dev and SimpleTalk_5_Prod, the difference in synonym definitions is now correctly identified and displayed.
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This adjustment applies not only to comparisons between databases on the same instance but is equally crucial when comparing databases across different instances. In scenarios where you have identical database names but different server instances (a common setup for development, QA, and production environments), unchecking this option ensures that SQL Compare accurately flags synonym differences arising from server name variations.
Broader Application Across Redgate Products
It’s important to note that this “Ignore database and server name in synonyms” option is not exclusive to SQL Compare. It’s a core setting within the SQL Compare engine, which powers a range of Redgate products designed for database development and deployment automation. Therefore, this same principle and option apply across tools such as:
- SQL Change Automation: For automating database deployments as part of your CI/CD pipelines.
- SQL Source Control: For integrating database changes with version control systems.
- Flyway Desktop: For database migrations and version control.
- Redgate Deploy (and its automation components): Redgate’s comprehensive suite for database DevOps.
If you are using any of these Redgate tools and find that synonym differences related to database or server names are not being detected or deployed as expected, verifying and unchecking the “Ignore database and server name in synonyms” option is a critical troubleshooting step.
Conclusion: Precise Synonym Comparisons for Reliable Deployments
Ensuring accurate database comparisons is paramount for reliable and consistent deployments. While SQL Compare’s default setting to ignore database and server names in synonyms is often helpful in streamlining deployments across environments with naming variations, it’s crucial to understand when and why to adjust this setting. Specifically, when you need to track and deploy synonym changes that involve different database or server targets, unchecking the “Ignore database and server name in synonyms” option in SQL Compare (and related Redgate tools) is essential.
By understanding and utilizing this option, you can unlock the full potential of SQL Compare for precise and comprehensive database comparisons, ensuring that even subtle differences in synonym definitions are accurately detected and managed throughout your database development and deployment lifecycle.
If you’re looking to enhance your database development and deployment processes with robust tools that offer granular control and accuracy, consider exploring the Redgate Deploy suite. Download a trial today and experience the power of precise database change management.
