In APA format a research article or scholarly article generally consists of a title, abstract, introduction, method, results and a discussion of the results. An article will also include citations and references of work that was used in writing the article. A good article will also include indications of the research provided and may offer some ideas for future study in the area.
An abstract includes a summary of the research or article that is to follow and is intended to give the reader an idea of what will be found within the article. An abstract explains the problem or topic the article is addressing. It may also briefly discuss the findings of the research as well as the method used in acquiring the information. Many online databases will use keywords in an abstract to properly categorize an article, making it easier to find by others.
APA format dictates that a full-text article include a title page, abstract, body (including methodology, results and discussion), conclusion and references. A full length article doesn't necessarily need to have an abstract, but an abstract can be beneficial to the amount of views an article may get by providing the reader an idea of the article content. A full article is generally several pages in length and an abstract is just a short paragraph at the beginning of the article.
It is useful to look at other abstracts in fields similar to the one in which you are writing to see how a typical abstract is conducted for that field of study. Some abstracts will include more information on the actual research conducted and some may not be quite as informative. Each article is different and may require a different format; a writer should know what is expected of him when constructing an abstract and a full-text article.