In This Chapter
Defining and applying OLAP
Retrieving OLAP data with Crystal Reports
Computer geeks have a maddening tendency to refer to things by inscrutable acronyms, sometimes even pseudo-acronyms, such as SQL — which, believe it or not, does not stand for Structured Query Language. (Read the sidebar on SQL to see why.) The letters in BASIC, FORTRAN, and COBOL once stood for something, as did the letters in the late, lamented SNOBOL. OLAP is a new entry in the list of obscure computer acronyms, but at least it's real. OLAP stands for On-Line Analytical Processing. In this case, the name does bear some resemblance to what the technology is actually about.
OLAP is a form of data mining that enables non-programmers to extract the information they need from an OLAP database. OLAP databases are structured differently from the way ordinary relational databases are structured, in order to make possible the retrieval of desired information using OLAP grids. With Crystal Reports, you can build OLAP grids that operate on OLAP databases, in effect pulling needles out of digital haystacks, without the aid of a formal query language such as SQL.
OLAP is called On-Line because it happens in real time, with the user sitting in front of the screen while there's a direct connection to a database. The results of user actions are immediate (more or less). The operation itself is called Analytical Processing because ...