[bsingh4]

None of the properties in the DatabaseInstance construct example posted above are defined as unions of strings - the TypeScript documentation link you just posted is irrelevant.

This is what one of the property types actually look like:

    /**
     * The MySQL or PostgreSQL version to
     * use. Can be `MYSQL_5_6`, `MYSQL_5_7`, `POSTGRES_9_6` or `POSTGRES_11` (beta) for second-generation
     * instances, or `MYSQL_5_5` or `MYSQL_5_6` for first-generation instances.
     * See [Second Generation Capabilities](https://cloud.google.com/sql/docs/1st-2nd-gen-differences)
     * for more information.
     */
    readonly databaseVersion?: pulumi.Input<string>;

In AWS CDK it was an easy task to select Postgres - in Pulumi case I had to read the comment.

[antics]

Oh, I see. Some properties that are not as well-typed as they could be, that's true. We are working on that. But there are lots of properties that do have good typing. Instance types, for example.