Take the second half of 2016 software designer afternoon test question 1 (15 points) as an example to analyze
In order to facilitate the provision of securities trading services, a stock exchange intends to develop a securities trading platform. The main functions of the platform are as follows:
(1) Account opening. According to the account opening information submitted by the customer service assistant, the account is opened, and the customer information is stored in the customer record, and the account information (balance, etc.) is stored in the account record.
(2) Deposits. Customers can make deposits into their accounts and modify account balances based on the deposit amount.
(3) Withdrawal. Customers can withdraw funds from their accounts and modify account balances based on the amount withdrawn.
(4) Securities transactions. Both clients and brokers can trade securities (online for clients and over the phone for brokers), and the transaction information is stored in the transaction records.
(5) Check the transaction. The platform reads transaction information from transaction records and returns transaction details to customers. The structured method is used to analyze and design the securities trading platform, and the context data flow diagram shown in Figure 1 and the 0-layer data flow diagram shown in Figure 2 are obtained.
[Question 1] (3 points)
Using the words in the description, give the names of the entities E1-E3 in Figure 1.
[Question 2] (3 points)
Using the words in the description, give the names of the data stores D1 to D3 in Figure 2.
[Question 3] (4 points)
Supplementary Figure 2 for the missing data flow and its start and end points based on terminology in the description and figures.
[Question 4] (5 points)
The actual securities transaction is usually completed in the securities exchange center, therefore, the "securities transaction" function of the platform needs to transmit the transaction information to the securities exchange center. For this functional requirement, please explain in 200 characters or less what modifications need to be made to Figure 1 and Figure 2.
analyse as below:
Data flow diagrams generally have two layers of data flow diagrams, as shown in Figure 1 and Figure 2 above. Figure 1 is the top-level data flow diagram, which is the parent diagram, and Figure 2 is the 0-layer data flow diagram, which is the sub-diagram. Mainly used to display system functions. It is displayed by the inflow and outflow data.
There are generally four elements:
Solid arrows represent data streams, and each data stream is represented by a well-defined name to reflect the meaning of the data stream;
The rounded rectangle or circle represents the processing of data, describing the transformation between the input data stream and the output data stream;
A rectangle with a double horizontal line or a missing vertical line indicates data storage, and data is stored in the form of a record file or a record table;
Rectangles represent data entities, people or organizations that exist outside of the software system. Origin and attribution of data:
Problem 1 Analysis:
Entity names are basically based on the descriptions given, and it is almost impossible to create names by yourself.
The title stem describes "account opening according to the account opening information submitted by the customer service assistant", so entity E1: customer service assistant
The stem description "customers can make deposits into their accounts and modify account balances based on the deposit amount", so entity E2: customer
The title stem describes "both clients and brokers can trade securities (clients online, brokers over the phone)", and can also be combined with subgraphs, so entity E3: Broker
Answers: E1: Customer Service Assistant, E2: Customer, E3: Broker
Problem 2 Analysis:
The stem description "and store customer information in the customer record, and account information (balance, etc.) in the account record." Combined with the subgraph,
D1 is the customer record, D2 is the account record,
The title stem describes ", store the transaction information in the transaction record.", so D3 is the transaction record
Answers: D1: Customer records, D2: Account records, D3: Transaction records
The first two questions are very simple.
Problem 3 Analysis:
The principle of missing data flow graph search: 1. The principle of balance between parent graph and subgraph. 2. The processing inside the subgraph must have input and output. It cannot be without input and only output (miracle), nor can only input without output (black hole), input The data stream is not enough to output (gray hole).
It should also be combined with the description of the title stem to find the missing data flow.
In the subgraph, deposits and withdrawals have only input data streams and no output data streams.
The starting point is "Deposit", the ending point is "D2", and the data flow name is: Modify account balance
The starting point is "withdrawal", the end point is "D2", and the data flow name is: Modify account balance
Securities transaction (online/telephone) processing has only data input, no data output, so it is missing.
The title stems describe "both clients and brokers can conduct securities transactions (on-line for clients and over the phone for brokers) and store transaction information in transaction records."
So the starting point is "securities transaction (online)", the end point is "D3", and the transaction information is stored in the transaction record
So the starting point is "securities transaction (telephone)", the end point is "D3", and the transaction information is stored in the transaction record
Answer:
Data flow name: Modify account balance, start point: deposit, end point: D2.
Data flow name: modify account balance, start point: withdrawal, end point: D2.
Data stream name: transaction information is stored in transaction records (online), starting point: securities transaction (online), end point: D3.
Data flow name: transaction information is stored in transaction record (telephone), starting point: securities transaction (telephone), end point: D3.
Problem 4 Analysis:
The stock exchange is not represented in the subgraph, so it is an external entity.
Figure 1 Add external entity "Securities Trading Center", add "Securities Trading Platform" to "Securities Trading Center", data flow: transaction information.
Figure 2 Add external entity "Securities Trading Center", add "Securities Trading (Online)" to "Securities Trading Center", data flow: transaction information.
Figure 2 Add "Securities Trading (Telephone)" to "Securities Trading Center", data flow: transaction information