Broadly speaking a Report Generator is an application whose purpose it is to take data from a source such as an XML data feed and then use it to produce a document in a format which satisfies a particular human readership.

Report generation functionality is almost always present in database systems, where the source of the data is the database itself. It can also be argued that report generation is part of the purpose of a Spreadsheet

Spreadsheet

A spreadsheet is a computer application that simulates a paper accounting worksheet. It displays multiple cells usually in a two-dimensional matrix or grid consisting of rows and columns. Each cell contains alphanumeric text, numeric values or formulas...

. Individual report generators also exist, however, to allow other types of report to be created, such as the HTML dynamic documents produced by the application QuSheet.

Information Systems

Information systems

Information Systems is an academic/professional discipline bridging the business field and the well-defined computer science field that is evolving toward a new scientific area of study...

theory specifies that information delivered to a target human reader must be Timely, Accurate and Relevant. Report generation software targets the final requirement by making sure that the information delivered is presented in the way most readily understood by the target reader.