Error establishing a database connection

Hi, I stupidly deleted all postmeta before a certain date and committed the changes. I now understand some of the first postmeta entries are required for wordpress to run. Is there a simple fix to this? I am considering just copying the initial postmeta entries from a fresh wordpress install. Is there any problem with this or a better solution? At the moment when i go to the site it says “Error establishing a database connection.” This happened immediately after deleting the postmeta. Thanks in advance!