I need the answers for those questions as soon as posible please in systems anal
ID: 3684791 • Letter: I
Question
I need the answers for those questions as soon as posible please in systems analysis and design book.
1- Define detail reports, exception reports, and summary reports. Explain the concept of a control field and how it is used to produce a control-break report.
2- Describe 5 principles for a user-centered interface design.
3- Describe a primary key, candidate key, secondary key, foreign key, and common field. What is meant by referential integrity?
4- What is the criterion for a table design to be in first normal form? How do you convert an unnormalized design to 1NF? What are the criteria for a table design to be in second normal form? How do you convert a 1NF design to 2NF? What are the criteria for a table design to be in third normal form? How do you convert a 2NF design to 3NF?
5- List the sections of a system design specification, and describe the contents.
Explanation / Answer
1.
-Detail Report produces one or more lines of output for each record processed.
-Exceprtion Report, only displys those records that met a specific conditions.
-Summary Report, used by indiviuals at higher levels in the organization that includes less details than reports used by lower level employees.
-A Controle field controls the out put of a report. When the value of a control field changes, a Control break occurs.
-A Control Break usually causes specific actions, such as printing sub totals for a group of records.
2.I’ve outlined below 5 principles of user-centered interface design, principles to help our websites and applications keep us on track.
these principles can be applied to any interface, or anytime someone has a point of contact with a digital or mechanical system. An interface can be a navigation menu, a search field, a dialog box, a selection pointer, a tools palette, a drag-and-drop feature, a web form, a simple button, and so much more.
Principle #1: Understand Your Users and Support Their Goals
Principle #2: Make Your Interface Easy to Learn and Enjoyable to Use
Principle #3: Remain Consistent
Principle #4: Form a Dialog with Your Users
Principle #5: Be Problem Free
3. SQL Constraints:
SQl Constraints are rules used to limit the type of data that can go into a table, to maintain the accuracy and integrity of the data inside table.
Constraints can be divided into following two types,
Primary Key Constraint
Primary key constraint uniquely identifies each record in a database. A Primary Key must contain unique value and it must not contain null value. Usually Primary Key is used to index the data inside the table.
Example using PRIMARY KEY constraint at Table Level
Candidate Key
Candidate keys are those keys which is candidate for primary key of a table. In simple words we can understand that such type of keys which full fill all the requirements of primary key which is not null and have unique records is a candidate for primary key. So thus type of key is known as candidate key. Every table must have at least one candidate key but at the same time can have several.
Secondary Key or Alternative Key
A table may have one or more choices for the primary key. Collectively these are known as candidate keys as discuss earlier. One is selected as the primary key. Those not selected are known as secondary keys or alternative keys.
For example in the table showing candidate keys above we identified two candidate keys, studentId and firstName + lastName. The studentId would be the most appropriate for a primary key leaving the other candidate key as secondary or alternative key. It should be noted for the other key to be candidate keys, we are assuming you will never have a person with the same first and last name combination.
Foreign Key Constraint
FOREIGN KEY is used to relate two tables. FOREIGN KEY constraint is also used to restrict actions that would destroy links between tables.
Example using FOREIGN KEY constraint at Table Level
Common Field:
Fields describe a single aspect of each member of a table. A student record, for instance, might contain a last name field, a first name field, a date of birth field and so on. All records have exactly the same structure, so they contain the same fields. The values in each field vary from record to record, of course. In some database systems, you’ll find fields referred to as attributes
4.normalisation: The process of structuring data to minimise duplication and inconsistencies. The process usually involves breaking down a single table into two or more tables and defining relationships between those tables. Normalisation is usually done in stages, with each stage applying more rigourous rules to the types of information which can be stored in a table. While full adherence to normalisation principles increases the efficiency of a particular database, the process can become so esoteric that you need a professional to create and understand the table design. Most people, when creating a database, don’t need to go beyond the third level of normalisation, called third normal form. And there’s no need to know the terminology: simply applying the principles is sufficient.
The first three levels in normalising a database are:
First Normal Form (1NF): There should be no repeating groups in a table.
For example, say you have a students table with the following structure:
student ID
name
date of birth
advisor
advisor’s telephone
student
course ID 1
course description 1
course instructor 1
course ID 2
course description 2
course instructor 2
The repeating course fields are in conflict with first normal form.To fix the problems created by such repeating fields, you should place the course information in a separate course table, and then provide a linking field (most likely student ID) between the students table and the course table.
Second Normal Form (2NF): No non-key fields may depend on a portion of the primary key.
For example, say we create a course table with the structure:
student ID
course ID
course description
course instructor
We can create a unique primary key by combining student ID + course ID (student ID is not unique in itself, as one student may take multiple courses; similarly, course ID is not unique in itself as many students may take the same course; however, each student will only be taking a particular course once at any one time, so the combination of student ID + course ID gives us a unique primary key).
Now, in 2NF, no non-key fields (course description, course instructor) may depend on a portion of the primary key. That, however, is exactly what we have here: the course instructor and course description are the same for any course, regardless of the student taking the course.
To fix this and put the database in second normal form, we create a third table, so our database structure now looks like this (with key fields in italics):
Student table
student ID
name
date of birth
advisor
advisor’s telephone
Student courses table
student ID
course ID
Courses table
course ID
course description
course instructor
Third Normal From (3FN): No fields may depend on other non-key fields. In other words, each field in a record should contain information about the entity that is defined by the primary key.
In our students table, for example, each field should provide information about the particular student referred to by the key field, student ID. That certainly applies to the student’s name and date of birth. But the advisor’s name and telephone doesn’t change depending on the student. So, to put this database in third normal form, we need to place the advisor’s information in a separate table:
Student table
student ID
name
date of birth
advisor ID
Student courses table
student ID
course ID
Courses table
course ID
course description
course instructor
Advisor table
advisor ID
advisor name
advisor telephone
5.
System Design Specification:The System Design Specification (SDS) is a complete document that contains all of the information needed to develop the system. Unlike the SRS, the target audiences of this document are the implementation and testing teams, so the SDS should be written at a more technical level.
The major sections of the SDS should be:
1. Introduction
2. Project Scope
3. System Design
4. Component and Process Design
5. Data Design
6. User Displays and Output Reports
7. System Files
8. Prototype Description
9. Prototype Test Procedures
10. Prototype Analysis
11. System Development and Project Management Schedules
12. Special Notes
13. Project Extensions
14. Appendices