While there is a difference between a database and a catalog, there's some similarities too.
One thing to note is our Discovery catalog searches through physical items belonging to TCC and a lot of our online databases all at once, so you don't have to choose a database! The catalog can be a good way to cast a wide net to see what is available. Learn some tips on how to search the Discovery catalog here.
You will get different results when you search a database directly depending on your search string and limiters because each database has different defaults and ways of filtering (for example, some databases will let you filter to articles written by a nurse. That's not a limiter in the catalog!).
Databases and catalogs are a lot like cars, once you know how to use one, you can probably navigate your way through all the others. But each database has its own interface and modes of retrieving. Each displays the results a bit differently, depending on a number of factors. So it never hurts to try multiple places just to make sure!
It is important to state that Discovery does not search through all of our databases. Some databases simply do not integrate well with the catalog. Sometimes, there are better limiters (search features) for the databases (like how the one mentioned here can limit to an article written by a nurse - the catalog cannot do that).
On the other hand, only searching one database directly, like EBSCOhost's Academic Search Premier, for example, may limit you from seeing what the other databases offer. It can really only tell you what is in that specific database, not, say, what is in Gale's Academic OneFile database too. Discovery, however, pulls from both at the same time AND will show you results that include our print and physical collections. So, when searching a database, you won't see DVD or print book options, though you might see ebook results (in full or broken up by section, such as by chapters). Discovery will show you a mix of online and print/physical materials available unless you filter them out. If you don't need, say, a print book, then searching the databases might be just fine.
Another consideration is interlibrary loan. The Discovery catalog will show you items (unless you filter them out) that we don't hold in our library, but could possibly get via interlibrary loan (ILL). It's worth knowing all your options sometimes, but other times you might not have time to wait on an ILL to arrive for your research anyway.
The Discovery catalog can easily locate a book if you enter the ISBN. It also does really well with a title search (see this example). You can play around with built-in search limiters in the Advanced Search, so you don't even have to remember the search string shortcuts like "ti:" or "su:" or "au:" (for title, subject, or author) that you may have heard about.
If using Google Scholar, it is great to use the Discovery catalog in conjunction with it and your online searching in general. If you run into a paywall, copying and pasting the title, sometimes using quotation marks around it (here's an example), can get you to free access options (either through Discovery showing you what database we have that offers access to that particular article or through offering the ILL option).
A little case study for why you would want to search Discovery directly, rather than the Find > Books or Find > Videos option links on the library homepage is this: What if you wanted to see if the library had both the film AND the book the film is based on of The Kite Runner in one search? Discovery is more likely to show you that we hold both in one step:
We hope this gives a glimpse for under what scenarios you would want to use the Discovery catalog and under what scenarios you would want to search a database directly!