WPDB Insert or if exists Update

I’m not crazy familiar with WPDB or SQL in general but I have a custom table for my project and I’m trying to assign some metadata to it. What I’d “like” to happen is if a row exists, update it and if not insert it. I’ve read both Insert and Update in the WPDB Codex but neither really went into an “either or” situation. I thought i could work with update, so my code so far looks like this:

Sharing database for collaborative development

Is there a straightforward way to share/sync multiple WP instances with a single database? I work collaboratively with several developers on custom themed sites. We use git to keep our files in order and it’s all fine in the early stages, but once content, plugins etc. start coming into play, we have issues with staying in sync with content.