Arranging information in tabular form
Sometimes it is better and more convenient to arrange information in a tabular form. This makes it easier for the reader to understand and comprehend the information and hence designing, coding, and testing become less challenging. As an example, let us look at the following definitions used for identifying different data functions in the function point analysis taken from International Function Point User’s Group (IFPUG) Counting Practices Manual (CPM 4.1).
External Inputs
An external input (EI) is an elementary process that processes data or control information that comes from outside the application boundary. The primary intent of an EI is to maintain one or more ILFs and/or to alter the behavior of the system.
External Outputs
An external output (EO) is an elementary process that sends data or control information outside the application boundary. The primary intent of an external output is to present information to a user through processing logic other than, or in addition to, the retrieval of data or control information. The processing logic must contain at least one mathematical formula or calculation, or create derived data. An external output may also maintain one or more ILFs and/or alter the behavior of the system.
External Inquiry
An external inquiry (EQ) is an elementary process that sends data or control information outside the application boundary. The primary intent of an external inquiry is to present information to a user through the retrieval of data or control information from an ILF or EIF. The processing logic contains no mathematical formulas or calculations, and creates no derived data. No ILF is maintained during the processing, nor is the behavior of the system altered.
It is difficult to understand these definitions and one has to read them a number of times to understand what is the difference between EI, EO, and EQ and in which case a function would be classified as EI, EO, or EQ.
Now the same information is presented in the tabular form as follows:
This table simply says that a function can alter the behaviour of the system, it can maintain one or more ILFs, and/or it can present information to the user. The next step is to determine whether it is EI, EO, or EQ. For that we have to determine what is the primary intent (PI) of the function and in addition to this primary intent, what else does it do. Identification of EQ is simple - in this case the only thing a function does is present
information to the user, which is also it’s primary intent. If it alters the behaviour of the system or maintains and ILF then it can either be an EI or and EO but not an EQ. On the other hand if the primary intent of the function is to present information to the user but at the same time it also performs any of the first two operations, it is an EO. Finally, if the primary intent of the function is either to alter the behaviour of the system of maintain one or more ILFs, then it is an EI.
Hence by putting and organizing the information in the form of a table, we have not only made it simple to understand the definition but also given an holistic picture which was not easily visible otherwise. Let us look at another example. This time the information is taken from the Income Tax Ordinance of Pakistan 2001. Consider the following statement that describes the income tax rates applicable to people with different brackets:
If the taxable income is less than Rs. 60,000, there will be no income tax. If the income exceeds Rs. 60,000 but is less than Rs. 150,000 then income tax will be charged at the rate of 7.5% for income exceeding Rs. 60,000. If the income exceeds Rs. 150,000 but does not exceed Rs. 300,000 then the income tax will be computed at 12.5% of the amount exceeding Rs. 150,000 plus Rs. 6,750. If the income exceeds Rs. 300,000 but does not exceed Rs. 400,000 then the income tax will be computed at 20% of the amount exceeding Rs. 300,000 plus Rs. 25,500. If the income exceeds Rs. 400,000 by does not exceed Rs. 700,000 then the income tax will be computed at 25% of the amount exceeding Rs. 400,000 plus Rs. 45,500. If the income exceeds Rs. 700,000 then the income tax will be computed at 35% of the amount exceeding Rs. 700,000 plus Rs. 120,500.
The same information can be organized in the form of a table, making it more readable and easier to use.
Once the information has been organized in the tabular form, in many cases it can be simply stored and mapped onto an array or a database table and the programming of this kind of a rule is simply reduced to a table or dictionary lookup. This reduces the complexity of the domain and hence reduces the over all effort for designing, coding, testing, and maintaining the system.
Our next post will be about Data Flow Model.
Sometimes it is better and more convenient to arrange information in a tabular form. This makes it easier for the reader to understand and comprehend the information and hence designing, coding, and testing become less challenging. As an example, let us look at the following definitions used for identifying different data functions in the function point analysis taken from International Function Point User’s Group (IFPUG) Counting Practices Manual (CPM 4.1).
External Inputs
An external input (EI) is an elementary process that processes data or control information that comes from outside the application boundary. The primary intent of an EI is to maintain one or more ILFs and/or to alter the behavior of the system.
External Outputs
An external output (EO) is an elementary process that sends data or control information outside the application boundary. The primary intent of an external output is to present information to a user through processing logic other than, or in addition to, the retrieval of data or control information. The processing logic must contain at least one mathematical formula or calculation, or create derived data. An external output may also maintain one or more ILFs and/or alter the behavior of the system.
External Inquiry
An external inquiry (EQ) is an elementary process that sends data or control information outside the application boundary. The primary intent of an external inquiry is to present information to a user through the retrieval of data or control information from an ILF or EIF. The processing logic contains no mathematical formulas or calculations, and creates no derived data. No ILF is maintained during the processing, nor is the behavior of the system altered.
It is difficult to understand these definitions and one has to read them a number of times to understand what is the difference between EI, EO, and EQ and in which case a function would be classified as EI, EO, or EQ.
Now the same information is presented in the tabular form as follows:
 |
| Information in Tabular Form - Click to Enlarge |
PI – Primary intent; M – may be; N/A – not allowed.
This table simply says that a function can alter the behaviour of the system, it can maintain one or more ILFs, and/or it can present information to the user. The next step is to determine whether it is EI, EO, or EQ. For that we have to determine what is the primary intent (PI) of the function and in addition to this primary intent, what else does it do. Identification of EQ is simple - in this case the only thing a function does is present
information to the user, which is also it’s primary intent. If it alters the behaviour of the system or maintains and ILF then it can either be an EI or and EO but not an EQ. On the other hand if the primary intent of the function is to present information to the user but at the same time it also performs any of the first two operations, it is an EO. Finally, if the primary intent of the function is either to alter the behaviour of the system of maintain one or more ILFs, then it is an EI.
Hence by putting and organizing the information in the form of a table, we have not only made it simple to understand the definition but also given an holistic picture which was not easily visible otherwise. Let us look at another example. This time the information is taken from the Income Tax Ordinance of Pakistan 2001. Consider the following statement that describes the income tax rates applicable to people with different brackets:
If the taxable income is less than Rs. 60,000, there will be no income tax. If the income exceeds Rs. 60,000 but is less than Rs. 150,000 then income tax will be charged at the rate of 7.5% for income exceeding Rs. 60,000. If the income exceeds Rs. 150,000 but does not exceed Rs. 300,000 then the income tax will be computed at 12.5% of the amount exceeding Rs. 150,000 plus Rs. 6,750. If the income exceeds Rs. 300,000 but does not exceed Rs. 400,000 then the income tax will be computed at 20% of the amount exceeding Rs. 300,000 plus Rs. 25,500. If the income exceeds Rs. 400,000 by does not exceed Rs. 700,000 then the income tax will be computed at 25% of the amount exceeding Rs. 400,000 plus Rs. 45,500. If the income exceeds Rs. 700,000 then the income tax will be computed at 35% of the amount exceeding Rs. 700,000 plus Rs. 120,500.
The same information can be organized in the form of a table, making it more readable and easier to use.
| Income | Tax |
|---|---|
| Less than Rs. 60,000 | 0% |
| Between Rs. 60,000 and Rs. 150,000 |
7.5% of (Income - 60,000) |
| Between Rs. 150,000 and Rs. 300,000 |
12.5% of (Income - 150,000) + 6,750 |
| Between Rs. 300,000 and Rs. 400,000 |
20% of (Income - 300,000) + 25,500 |
| Between Rs. 400,000 and Rs. 700,000 |
25% of (Income - 400,000) + 45,500 |
| Greater than Rs. 700,000 | 35% of (Income - 700,000) + 120,500 |
Once the information has been organized in the tabular form, in many cases it can be simply stored and mapped onto an array or a database table and the programming of this kind of a rule is simply reduced to a table or dictionary lookup. This reduces the complexity of the domain and hence reduces the over all effort for designing, coding, testing, and maintaining the system.
Our next post will be about Data Flow Model.
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