Article: A self-contained nonfiction prose composition on a fairly narrow topic or subject, written by one or more authors and published under a separate title in a periodical containing other works of the same form.
Periodical: A publication appearing at regular (or irregular) intervals with its own distinctive title, containing a mix of articles, editorials, reviews, columns, short stories, poems, or other short works written by more than one contributor, issued in soft-cover more than once. Examples include journals, magazines, and newspapers.
Database: A large, regularly updated file of digitized information (bibliographic records, abstracts, full-text documents, images, statistics, etc.) related to a specific subject or field, consisting of records of uniform format organized for ease and speed of search and retrieval, and managed with the aid of a database management system software.
Articles are in periodicals, and multiple periodicals are in databases. Sometimes not everything in a periodical will be available in a database. In this case, it's best to go to the print copy!
Library databases provide access to articles and other information; sometimes the full text is available but sometimes only the abstract and citation information are available (in which case you can request the item through interlibrary loan). Databases can include access to peer-reviewed articles, magazine articles, newspaper articles, etc. Some are specialized by topic, and some are interdisciplinary. Milne Library subscribes to hundreds of databases. Those listed below are a good start for your work in this class:
The following video on Academic Search Complete (a database that covers a broad range of topics) will provide excellent strategies that you can utilize with other databases.