Databases are designed to help you find information. When you shop or look for movies or ideas on Amazon, Netflix, or Pinterest, you are using a database.
Databases have tools to help you find information -- for example, Netflix lets you search for movies by name or by genre. Library databases have tools to help you find information you need for your academic work.
One way to think about databases is to think about organizing a drawer.
If you throw a lot of stuff randomly into a drawer, it’s a collection but it’s not an organized, searchable collection -- and it will be hard to find what you’re looking for.
It’s also helpful if you know what kind of information is in the drawer. If you know your drawer has socks, photos, and letters, you probably aren’t going to find dog food there. Library databases include information about what you can find -- so you know you’re searching in the right place before you start.