How to migrate the posts from an old custom legacy blog to a new WordPress website?

I have to migrate the posts of a very old custom legacy blog made in ASP (the posts are stored in a MySql table) into a new WordPress blog.

So I need your help to find the smartest solution to do it, I rule out the idea of ​​doing it manually because the number of posts that should be migrated is really high.

So looking this ER schema: http://codex.wordpress.org/images/9/97/WP3.8-ERD.png
I thought I could create a script that take a post from the post table of my old legacy blog and create a new record on the wp_posts wordpress post table of the new blog.

Is it a good solution or exist something better? A WP plugin on something like this?

Tnx

Old unanswered question, but found this via the googles (1st answer) that appears to have good info / links (might be useful to someone):

What is the required format for importing posts into WordPress?

Plus this one from the Codex, which has info on importing from all sorts of formats, including RSS and XML. https://codex.wordpress.org/Importing_Content

If your old blog can export to one of those formats (or you can write a custom exporter into those formats), those links could give you a start.