RDS and Aurora to invoke AWS Lambda Function Directly

You are correct that RDS PostgreSQL, Aurora PostgreSQL, and Aurora MySQL have the capability to invoke AWS Lambda functions directly. However, for the other RDS database engines you mentioned, there is currently no direct built-in support for invoking Lambda functions.

For RDS IBM DB2, RDS Microsoft SQL Server, RDS MySQL, and RDS MariaDB, there is no native functionality to directly invoke Lambda functions from within the database itself. These database engines do not have the same level of integration with AWS Lambda as their PostgreSQL and Aurora counterparts.

If you need to integrate these other RDS database engines with Lambda, you would typically need to use an intermediary service or application layer to invoke the Lambda functions. This could involve creating an application that interacts with both the database and Lambda, or using other AWS services as a bridge between your database and Lambda functions.

It's worth noting that the ability to invoke Lambda functions directly from within the database is a more advanced feature that is currently limited to specific database engines and versions in the AWS RDS and Aurora offerings. If this functionality is crucial for your use case, you may want to consider using one of the supported database engines (RDS PostgreSQL, Aurora PostgreSQL, or Aurora MySQL) that offer this capability.
Sources
Invoking an AWS Lambda function from an Aurora PostgreSQL DB cluster - Amazon Aurora
10 Amazon Aurora tips for application developers – Part 2 | AWS Database Blog
Invoking an AWS Lambda function from an RDS for PostgreSQL DB instance - Amazon Relational Database Service
Invoking a Lambda function from an Amazon Aurora MySQL DB cluster - Amazon Aurora