getting the problem domain of the database back in focus

GETTING THE PROBLEM DOMAIN OF THE DATABASE BACK IN FOCUS HOW TO

Include the specific cases that the particular function cares about.īe sure to include an else case to handle the others in the template and to When creating tests and templates for a particular function Operating on KeyEvent may only care about the space key and justignoreĪll other keys, the following would be an appropriate template forįunctions operating on enumerations should generally have at leastĪs many tests as there are cases in the enumeration. At that point include the specificĬases that function cares about. Instead write one or two, as wellĪs a comment saying what the others are, where they are definedĭefer writing templates for such large enumerations until a template It is not necessary to write out all theĬases for such a data definition. KeyEvent includes all the letters of the alphabet as A canonical example is KeyEvent provided as Note that some enumerations contain a very large number ofĮlements. =) to construct the questions of each clause. Use equality predicates ( string=?, key=?, Template: For enumerations the template is a condĮnumeration. Use simple atomic data when the information to be represented is itselfĪtomic in form, such as the elapsed time since the start of the animation or While doing so add new functions to the wish lists to follow the one function per task rule.Īs the structure of the data definition changes, the main affected parts of the HtDF recipe are the examples and the template. What does the function have to work with? Set up functional examples using check-expect, check-error.Signature, purpose statement, and stub.Recall, the design of a function proceeds in several steps. Maintain a wish list of desired functions, starting with your initial one.

GETTING THE PROBLEM DOMAIN OF THE DATABASE BACK IN FOCUS HOW TO

Refernce, here are the steps again of: How to Design Functions (HtDF) This column indicates connections between a data definitionĪnd the process of a designing function to process that data. The remainder of this page presents those different forms We will study several forms of information and data in theĬourse.

and therefore much of the final program design.

which in turn determines the form of the examples and the templates,.

the form of information in the problem's domain determines the.

One of the most important points of this course is that:

A template for a function operating on the data.

An interpretation comment that describes how data of that form should be interpreted as information.

A types comment that describes how the information is represented as data.

A possible structure definition ( define-struct) (after week 3).

This column goes through the different kinds of data definition, the column to the right discusses how each kind affects the HtDF recipe.Ī data definition consists of four or five parts: The shape of the data definition determines how many tests are required to achieve complete coverage it also determines the template or inventory of what the body of the function has to work with.ĭata definitions come in a number of different kinds, and each kind has different implications for the HtDF recipe.

In addition, the data definition interacts with the How to Design Functions (HtDF) process for the tests (functional examples) and the template/inventory.A data definition for the WorldState is required to design a World program.Data definitions for the parameters are required to write the signature of a function.It must also describe how to interpret a data value as information in the program's domain.ĭata definitions are the foundation for the HtDP process: Data in the program can be interpreted as information in the problem.Ī data definition must describe how to make data that satisfies the data definition and how to tell whether a data value satisfies the data definition.Information in the problem domain is represented by data in the program.Program, explaining how we intend to represent(/interpret) information(/data): This web page summarizes the process of developing a data definition, with a particular focus on the interaction between the different shapes of domain information, program data, test cases and templates.Ī data definition establishes the relationship between problem domain and

Getting the problem domain of the database back in focus