How do I change the address in the database?

Hello everyone

I decided to reinstall my local installation of Discourse
I deleted the /discourse folder
I repeated all the steps from the manual Beginners Guide to Install Discourse on Ubuntu for Development
But the database remained
Previously, my discourse was on localhost: 3000
And now I’m being transferred to localhost:4200
Because of this, my installation cannot find images on the site
And they are displayed as empty

I didn’t know how to delete it. Please tell me how to delete the database or how to change localhost: 3000 to localhost:4200 in it