How to batch edit old topics (replace text-links)

Hi everyone, please help me, i have problem.

I have a wordpress blog with domain (x), i used to use another domain but i lost it, so most of my topics/posts on my blog need to be changed in the content, namely, i have been changing the old domain link to the new domain link, and because i have many posts, it is taking all my time.

I wonder if there is a way to edit all posts in batch process, i just want to replace text, for example:

replace olddomainname.com with newdomainname.eu

I have been editing my posts one by one with notepad, i copy the text on the post, then paste it on notepad, and then i batch replace the text i want to replace, but i want to do it quickly to all my wordpress blog posts.

Do i have to edit the database, is that dangerous? Or is there another way or a safer way, please tell me if you know.