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1. Phase II :System Analysis

   Prepared by Ejlal Al-khuzaie
2. Phase Outline Introduction Requirements Collection Interviews Questionnaires Requirements Analysis Data Flow Diagram (DFD) Process Specification Entity Relationship Diagram (ERD) Data Dictionary Prepared by Ejlal Al-khuzaie
3. Introduction What is your purpose of this phase ?! What is going to be earn from doing this document ?! Prepared by Ejlal Al-khuzaie
4. Requirements Collection Interview In this section you will insert all result you got for inter Interview outline Prepared by Ejlal Al-khuzaie
5. Requirements Collection ( cont … ) Interview Questions Nature of his her job , job experience Current System Suggestions to improve the system Prepared by Ejlal Al-khuzaie
6. Requirement Collection Preparing the questions List all the items about which information is required Decide who will be able to give you this information Decide on the question type: Multiple choice Yes/No Open questions etc…. Write questions on separate pieces of paper When all questions are worded, sort them in order Prepared by Ejlal Al-khuzaie
7. Requirement collection Assess the questionnaire Give it to three to five people and check how they answer the questions Ask the respondents for feedback on the questionnaire: How difficult was it? Were there any questions they were unsure about? Make adjustments based on the comments you received Distributing and gathering Decide how the questionnaire would be distributed Start recording data as soon as the questionnaires are received Prepared by Ejlal Al-khuzaie
8. System Requirement Functional Requirement Statements of services the system should provide. How the system should react to a particular input. How the system should behave in a particular situation. Generally, functional requirements are expressed in the form "system shall do <requirement>“ Prepared by Ejlal Al-khuzaie
9. System Requirement Non-Functional Requirement Statements of system constraints. Define system properties such as reusability, portability, efficiency, integrity, flexibility, usability … etc. non-functional requirements are "system shall be <requirement>" Prepared by Ejlal Al-khuzaie
10. System Requirement Functional Requirement : Non-Functional Requirement : Prepared by Ejlal Al-khuzaie
11. DFDs You may use either of these two conventions, just don’t mix them Prepared by Ejlal Al-khuzaie
12. DFDs Entities: can be people, departments, other companies, other systems… are called sources if they are external to the system and provide data to the system, and sinks if they are external to the system and receive information from the system Processes must have at least one input and at least one output at the primitive level are labeled with verb + object (e.g. “print invoice” or “add customer”) (e.g. in the hierarchy below, none of the processes are primitive) at the non-primitive level, are labeled more generally (e.g. “customer maintenance” or “warehouse reports”) Prepared by Ejlal Al-khuzaie
13. DFDs Data stores: can be online or “hard copy” (see notes on logical VS physical DFD’s below) are labeled with a noun (e.g. the label “customer” indicates that information about customers is kept in that data store) data is stored whenever there are more than one process that needs it and these processes don’t always run one after the other (if the data is ever needed in the future it must be stored) Prepared by Ejlal Al-khuzaie
14. DFDs Data flows: must originate from and/or lead to a process (this means that entities and data stores cannot communicate with anything except processes –remember that it takes a process to make the data flow) can go from process to process, but that does imply that no data is stored at that point can have one arrowhead indicating the direction in which the data is flowing can have 2 arrowheads when a process is altering (updating) existing records in a data store Prepared by Ejlal Al-khuzaie
15. DFDs General rules Each process must have a minimum of one data flow going into it and one data flow leaving it. Each data store must have at least one data flow going into it and one data flow leaving it. Data in data stores must be used (data shown flowing out) otherwise there is no reason to store it. Data must also be updated (new data shown flowing in) otherwise it will be obsolete and will not have been updated by the system. A data flow out of a process should have some relevance to one or more of the data flows into a process. Prepared by Ejlal Al-khuzaie
16. DFDs Data stored in a system must go through a process. Data cannot be filed directly from an external entity (terminator) or retrieved directly by an external entity. This would be classified as a breach of security! A person or business outside another business should not have direct access to another business's filing system. Similarly, filing systems within an organization cannot logically communicate with one another unless there is a process involved. One data store cannot have a direct link to another data store. All processes in DFDs must be linked to either another process or a data store. A process cannot exist by itself, unconnected to the rest of the system. Prepared by Ejlal Al-khuzaie
17. DFDs Context level Represents a system at a high level. Shows the overall business process as just one process Shows all the outside entities that receive information from or contribute information to the system Level 0 Shows all the processes that comprise the overall system Shows how information moves from and to each process Adds data stores Prepared by Ejlal Al-khuzaie
18. DFDs Level 1 It represents the process in more detail Each level 1 diagram relates to a single process on the corresponding level 0 diagram. Level 1 diagrams may not be needed for all level 0 processes Prepared by Ejlal Al-khuzaie
19. Example A customer order a meal , the system check meal ingredient , the order will reach the kitchen to be prepared . The customer will receives a receipt of his order. Prepared by Ejlal Al-khuzaie
20. Context level Prepared by Ejlal Al-khuzaie
21. Level 0 Prepared by Ejlal Al-khuzaie
22. Process Specification Structure English Define process Process ID Process Name Process Description Input : Logic : CHECK IF THEN Check IF Then Change Else IF Remark Prepared by Ejlal Al-khuzaie
23. Process Specification Decision Table Concept Layout Prepared by Ejlal Al-khuzaie
24. Process Specification Entity Relationship Diagram ( ERD ) Entity Relationship Diagrams ( ERDs ) illustrate the logical structure of database. Prepared by Ejlal Al-khuzaie
25. Data Dictionary Defining Dataflow ID: Name : Description Source : Destination: Type: Type of data flow , either a record entering or leaving a file containing report form , or screen , internal-used between processes The volume per unit time Commment Prepared by Ejlal Al-khuzaie
26. Data Dictionary Defining Data Structures The symbols used are: Equal sign , meaning “ consists of” Plus sign , meaning “ and” Braces {} meaning repetitive elements , a repeating element or group of elements Brackets [] for an either/or situation Parentheses () for an optional element Prepared by Ejlal Al-khuzaie
27. Data Dictionary Example Customer order = customer number + customer name + address + Telephone + order date + { order Items } + order Total + method of payment + (credit card type ) + credit Card Number ) + (Expiration Date ) Prepared by Ejlal Al-khuzaie
28. Data Dictionary Defining Elements Name Customer Number Alias Client Number Description Uniquely identifies a customer that has made any business transaction within the last five years. Length 6 Input Format X(6) Output Format X(6) Default Value Continuous/Discrete Continuous Type Sting Base or Derived Derived Upper Limit <999999 Lower Limit >18 Comments The customer number must pass a modulus-11 check-digit test. Prepared by Ejlal Al-khuzaie
29. Data Dictionary Base or Derived A base element is one that has been initially keyed into the system A derived element is one that is created by a process , usually as the result of a calculation or some logic. Prepared by Ejlal Al-khuzaie
30. Define Data Store ID D1 Name Member File Alias Description Contains a record for each member File Type Computer File Format Database Record Size 200 Maximum Records 45,000 Average Records 42,000 % Growth/Year 6% Prepared by Ejlal Al-khuzaie
31. Data Set/TableName Customer Data StructureCustomer Record Primary KeyCustomer Number Secondary KeysCustomer Name, Telephone, Zip Code Comments The Customer Master File records are copied to a history file and purged if the customer has not purchased an item within the past five years. A customer may be retained even if he or she has not made a purchase by requesting a catalog. Prepared by Ejlal Al-khuzaie
32. The Data Store ID The Data Store Name, descriptive and unique An Alias for the file A short description of the data store The file type, either manual or computerized If the file is computerized, the file format designates whether the file is a database file or the format of a traditional flat file The maximum and average number of records on the file The growth per year This helps the analyst to predict the amount of disk space required. The data set name specifies the table or file name, if known. The data structure should use a name found in the data dictionary Prepared by Ejlal Al-khuzaie