Report generator

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A report generator is a computer program for creating reports (also called reports) from data from a database or other data sources. So that reports can be created not only by software developers but also by end users, the database queries required for this are often defined via graphical user interfaces and the database-specific instructions, e.g. B. SQL generated automatically.

There are three main types of report generators:

  • Query-based report generators only offer the option of selecting and presenting within prefabricated data views ( queries ); however, they are usually easy to use. Query-based report generators are often part of BI products. The queries are often predefined by software developers.
  • Table-based report generators, on the other hand, allow the user to compile their own data views by individually linking the desired database tables as required. This assumes that the user has to know which data is in which tables. A certain knowledge of the data model ( ER model ) of the queried databases is essential for this, which limits the group of possible users.
  • Report generators that can be integrated into application programs as programming components. These can then - depending on the implementation - present themselves to the user as query-based or table-based.

In order to also give typical end users within the scope of end-user computing the opportunity to create reports on all available data, there are a number of approaches to simplify the operator guidance of table-based report generators. One method is to use the metadata that describe the meaning of the content of the individual tables with their columns and the relationships between the tables so that suggestions for possible links can be offered to the user.

In addition to numerous standard software products, report generators that are optimally tailored to the respective information requirements are often implemented as part of an individual solution . The report generators, which have a programming interface, are particularly suitable for this, as these can usually be adapted to individual requirements.

history

Report generators came onto the market as a novelty in the 1970s, the transition from the age of punched cards to computer workstations on the mainframe computers of the time. They should simplify the creation of lists and evaluations from sequential data (on punch cards, tape (tapes) or plates). The creation of programs (in COBOL, FORTRAN, ...) was usually reserved for IT departments, but the creation of reports should also be possible by clerks, according to the approach and the promise of the manufacturer.

For this purpose, simple languages ​​were defined that only provided basic structures (if ... then ... else, a type of loop, possibly jump commands), only offered basic mathematical functions and had convenient print commands. The typical report structure consisted of three blocks:

Starting block (optional)

Set start values, define page header, set column widths, ...

Processing block

Loop over each record of the data to be evaluated with evaluations, printing, ...

End block (optional)

Output summarizing end values

Typical for report generators were the waiver of explicit opening and closing commands for files, the automatically existing loop via a read record in the processing block and the silent termination of this loop when the end of the file is reached.

One representative was the Easytrieve program (Easy Retrieve = simple access) or Omnitab. The Awk created with UNIX was also initially a report generator.