AI Timesavers

Posted by Vito, posted March 19

As a programmer, AI really can be a great timesaver. When you're using multiple languages, platforms and handling databases, networking, and more, remembering every detail is impossible. How many people use AI regularly?

I asked Copilot a question about setting up a database trigger to save me the time of looking it up. Here is my question and Copilot's response:

[Question] What is the Formula needed to setup a Computed Column in SQL Server that updates the PostCount of the Topics table whenever there was an INSERT into the Posts table based on the TopicId of the post that was inserted?

[Response] In SQL Server, a computed column is calculated from an expression that can use other columns in the same table. However, it cannot be used to calculate aggregate values such as a count of rows in another table. Therefore, you cannot directly use a computed column to keep track of the PostCount in the Topics table based on inserts in the Posts table.

Instead, you can use a trigger on the Posts table to update the PostCount in the Topics table. Here’s an example of how you might set up such a trigger:

CREATE TRIGGER trg_UpdatePostCount ON Posts AFTER INSERT AS BEGIN UPDATE Topics SET PostCount = (SELECT COUNT(*) FROM Posts WHERE Posts.TopicId = Topics.TopicId) WHERE TopicId IN (SELECT DISTINCT TopicId FROM inserted) END;

In this trigger:

AFTER INSERT specifies that the trigger should run after an insert operation on the Posts table. The UPDATE statement updates the PostCount in the Topics table. The SET clause sets the PostCount to the count of posts in the Posts table that have the same TopicId. The WHERE clause ensures that only the topic related to the inserted post is updated. Please note that triggers can have performance implications, so they should be used judiciously. Also, this is a simple example and might need to be adjusted based on your specific schema and requirements. Always test thoroughly before deploying to a production environment.

Remember to replace Posts and Topics with your actual table names, and TopicId with your actual column names. Also, ensure that your database user has the necessary permissions to create triggers. If you’re unsure, consult with your database administrator.

I hope this helps! Let me know if you have any other questions.