Bản trả lời câu hỏi của Project(2)

8/9/2019 Bn tr li cu hi ca Project(2)

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Bn tr li cu hi ca Project

Question 1: What are the minimum configuration requirements to guarantee for new system

run safe and quickly?

Software requirement

The proposed system requirements at least the following software: For web server:

Microsoft Windows XP Professional/ Windows 2003 Server

MS.Net Framework 3.5

IIS 6.0 or higher

Mozilla, Internet Explorer 6.0 or higher

Microsoft SQLServer 2005

For web browser:

Window XP/Vista(all version)/ Window 7

Mozilla, Internet Explorer 6.0 or higher

Hardware requirement

For dedicated server side:

Intel Pentium IV 1.7 GHz or higher

1 RAM or higher

For client side:

At least Intel Pentium IV 800 MHz

32 bits resolutions monitor

56 Kbps transfer rate

Question 2: Which methods have you used in investigating progress?

Interview method, observation methods and questionnaire method

A, Interview method:Before the interview, you should contact the interviewee directly to set up an appointment and

agree with him/her on time, venue and interview objectives. During the interview, if you behave

professionally, you will receive the same attitude from your interviewee. Try to attentively listen

to the people youre talking to and take notes of all the necessary information you are providedduring the interview. The interview paper and minute are always useful for you and your

successor because it helps you master the origin of the information you have. Its important to

open and close the interview carefully because this may impact the way your questions areanswered. When opening the interview, try to do it in a trustful, respective way with our good

will. When closing the interview, you should recap the main points of the interview, make

arrangement for the following cooperation and leave the issues open for discussion between both

sides. Dont make the conversation too lengthy nor prepare too many questions to ask. The bestway is you prepare a short list of the main topic you want ask about.

B, Observation methods:

B1, Official observation: Its not a good method to observe every single element while collectinginformation to develop the system. The future system youre building up may be deemed to

change the current way of working. Moreover, those youre looking at may feel uncomfortable

and may behave unusually, which will affect your surveys quality.


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B2, Unofficial observation: In order to get an overview of an organization, take a look at its pile

of paper and document, interruption of work, unreasonable timing and positive reflection of a

good working environment Its also important to know the quantity of data that need to beprocessed and predict how they change over the time. Researching through documents is the

final good method to get important information.

C, Questionnaire method:This method requires your clear instructions to the user. A questionnaire can be designed base on

the following points:

Title: describe the objectives and main contents;Data classification: categories of data that will be used;

Data: contents of the data in each category.

In general, this method is complicated and ineffective for inexperienced analyzers.

Its clear that each method has its own strong and weak points and is suitable for particularcontents. However, regardless what method you use, the general principle is: The more

information you get about the operation environment of an organization, the more you

understand its issues and be able to make realistic questions about the matters youre interested

in. Information can be divided into 3 groups: General information of the organizations verticalstructure, information about the organization and information about the units that directly relate

to the current issues.

Question 4: What is Unofficial Observation and what is Interview method?

B, Observation methods:

B1, Official observation: Its not a good method to observe every single element while collectinginformation to develop the system. The future system youre building up may be deemed to

change the current way of working. Moreover, those youre looking at may feel uncomfortable

and may behave unusually, which will affect your surveys quality.B2, Unofficial observation: In order to get an overview of an organization, take a look at its pile

of paper and document, interruption of work, unreasonable timing and positive reflection of a

good working environment Its also important to know the quantity of data that need to beprocessed and predict how they change over the time. Researching through documents is the

final good method to get important information.

Question 6:Why do you choose Visual Basic/ C#/ Java/So what is Visual Basic? Visual refers to the method used to create what the user sees-the

graphical user interface, or GUI. :Basic refers to the BASIC (Beginners All- Purpose Symbolic

Instruction Code) programming language, a language used by more programmers than any otherlanguage in the history of computing. Visual Basic is a high level language. It is the fastest and

easiest way to create applications for Windows. Visual Basic provides you with a complete set of

tools to simplify rapid application development. It is used to create Graphical user Interface(GUI). It contains several hundred statements, functions, and keywords, many of which relate

directly to the Windows Graphical User Interface rather than writing numerous lines of code to

describe the appearance and location of interface elements, you simply drag and drop rebuiltobjects into place on the screen.

Visual Basic 2005 introduces new language features, including loop continuation, guaranteed

resource disposal, mixed access properties, unsigned and nullable data types, operator


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overloading, partial and generic types, custom events, and Common Language Specification

(CLS) compliance checking.

Continue Statement: Visual Basic now supplies a Continues statement, which

immediately skips to the next iteration of a Do, For, orWhile loop

Properties with Mixed Access Levels: Visual Basic now allows you to declare a

property with different access levels on its Get and Set procedures. Visual Basic nowsupports unsigned integer data types (UShort, UInteger, and ULong) as well as thesigned type SByte.

Nullable Types: Visual Basic now supports extensions of value types that can take

either their normal values or a null value. A null value is useful for indication that avariable has no defined value because the information is not currently available

Operator Overloading: Visual Basic now allows you to define a standard operator(such as +, &, Not, orMod) on a class or structure you have define.

Code Separation using Partial Types: Visual Basic now provides a mechanism to

allow the integrated development environment (IDE) to separate generated code fromyour authored code into separate source files. Most of the time, you only have to deal

with the code you wrote. Generic Types: Visual Basic now supports type parameters on generic classes,

structures, interfaces, procedures, and delegates. A corresponding type argument

specifies at compilation time the data type of one of the elements in the generic type.

Custom Events: Visual Basic now allows you to have greater control over the detailed

behavior of events. You can declare custom events by using the Custom keyword as

a modifier for the Event statement. In a custom event, you specify exactly whathappens when code adds or removes an event handler to or from the event, or when

code raises the event

Compiler Checking Options: Visual Basic 2005 introduces new compiler checking

options. The /nowarn and /warnaserror (Visual Basic) options provide more control

over how warnings are handles. Each one of these compiler options now takes a listof warning Ids as an optional parameter, to specify to which warnings the option

applies

o CLS Compliance checking: visual Basic now generates a warning for each line of

code that contains any specification or operation that the Common Language Specification

(CLS) does not support

o Uninitialized Variable Checking: Visual Basic now generates a warning for each

potentially uninitialized variable. A variable has this status if there is at least one possible

execution path that does not assign any value to the variable before using it

Question 7: Why do you choose SQL Server?

ISQL Server 2005, released in November 2005, is the successor to SQL Server 2000.It included native support for managing XML data, in addition to relational data. For this

purpose, it defined an XML data type that could be used either as a data type in database

columns or as literal in queries. XML columns can be associated with XSD schemas; XML databeing stored is verified against the schema. XML is converted to an internal binary data type

before being stored in the database. Specialized indexing methods were made available for XML

data. XML data is queried using XQuery queries in T- SQL. In addition, it also defines a newextension to Xquery, called XML DML, that allows query-based modifications to XML data.


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SQL Server 2005 also allows a database server to be exposed over Web services using TDS

packets encapsulated within SOAP requests. When the data is access over web services, results

are returned as XML.

For relational data, T - SQL has been augmented with error handling features and

support for recursive queries. SQL Server 2005 has also been enhanced with new indexing

alogorithms and better error recovery systems. Data pages are check summed for better errorresiliency, and optimistic concurrency support has been added for better performance.

Permissions and access control have been made more granular and the query processor handles

concurrent execution of queries in a more efficient way. Partitions on tables and indexes aresupported natively, so scaling out a database onto a cluster in easier. SQL CLR was introduced

with SQL Server 2005 to let integrate with the .NET Frameworks. SQL Server 2005 is the Data

Platform leader

For all these reasons above, we have chosen SQL Server 2005 for our projects.

Question 8: What is Database Management System?

A DBMS is a complex set of software programs that controls the organization, storage,

management, and retrieval of data in a database. DBMS are categorized according to their datastructures or types, some time DBMS is also known as Data base Manager. It is a set of

prewritten programs that are used to store, update and retrieve a Database Logical view andphysical view. A database management system provides the ability for many different users to

share data and process resources. But as there can be many different users, there are many

different database need

Question 9: Which stages should a system analysis process take place?

System analysis process in its most general form includes the following main steps:

Identify the operation of the existing system.

Understand what the existing system is doing.

Understand the need of the users. Decide on what of the new system should be doing

Decide on how the new system will function.

Question 10: What is data dictionary? What is data dictionarys function? Which parts should

be in data directorys contents? (7 items data flow external entity, process, data store, record,

data item, report)

The data dictionary is an organized listing of all the data elements pertinent to the system, with precise, rigorous definitions so that both user and systems analyst will have a common

understanding of all inputs, outputs, components of stores and intermediate calculations.

The data dictionary includes 7 parts:

- data store- process

- External entity

- Data flow

- Data item entity

- Record

- Report

Data store, process, external entity, data flow concern with symbol in Data Flow Diagram (DFD)


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Question 11:What is data element?

Describing the meaning of the flows and stores shown in the data flow diagrams

Begin - End

Process

Input - Output

Condition

Data Flow

Question 12: What is the purpose of FD?

Functional diagram (FD) or Function hierarchy diagram (FHD): is used to show systems

functions that will be constructed and the implementation process of data gram. Moreover, FD

will also be used to determine the appearance frequency of smaller process in the data flow chart.It only shows what to do not how to do. In the functional diagram, a function is divided into

many smaller functions and each smaller function contains even smaller ones.

Question 15: Why should the data dictionary be consistent with the data flow diagram?Because data dictionary helps analysers, designers to understand more details about DFD

Question 16: What are the process tools (flowchart, decision table, decision tree, pseudo code,

)

- Process description is actually detailing the systems requirements displayed function

diagram and data flow diagram. Some of the tool for process description are: block chart,decision table, structured language..Of those tools, structured language (structured

English) considered one of the most useful and popular tools for process description

because it is simple for users and other members taking part in developing the systems

life cycle.

- The process must be described by using one of the 3 main developed structures in thestructures programming: Oder, selective and repetitive.

- The process description is not any useful in the analysis process but is also used todescribe the designing process of the physical system and the programming process

afterwards.

Question 17: What is the purpose of diagram data flow (DFD)


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It describes the information flow in the system. The next step of system analysis is to consider in

detail the information necessary for the implementation of functions discussed above and the one

necessary for the improvement of the function. Modeling tool frequently used for this purpose isthe data flow diagrams (DFD)

Question 19: Which Symbol are often used in Data Flow Diagram+ The Process:

- The process is represented graphically as a circle or rectangle with rounded adges. The process

name describe what the process does.+ Data Flow:

- A flow is represented graphically by an arrow into or out of process.

+ The Store:

- The store is represented graphically by two parallel lines.External factors:

- External Factor tends to be represented by a rectangle, or shorter edge of which is omitted

while the other is drawn by a duplicated line.

Question 20: What is the context diagram?

The first step constructing a set of data flow diagrams for an information system is todraw DFD called context diagram

A context diagram is a data flow diagram that shows the boundaries of the information

system. The context diagram is a top level view of the information system.

Question21: How do you know what extertal entities and data flows must be placed in the

context diagram ? (Investigate the environment of the system to the define entities which

supply data for the system or receive information from the system)

You review the information systems requirement in detail to extract all external data sources

and destination. During this review and analysis be sure to record the name of the external

entities, the name and content of the data flows, and the direction of the data flows. If you do thiscarefully, you should have no difficulty drawing the context diagram. Your task of review and

analysis is made easier if you clearly defined the boundaries and scope of the information system

when you undertook requirements determination in the system analysis phase.

Question22: What is diagram level 0? And what part shoule be used in Level 0?

Diagram 0 is a data flow diagram that gives a more detailed view of an informationisystem than does the context diagram.

On diagram 0, you show the major processes, data flows, and data sores for the

information system. In addition, you repeat the external entities and data flows that

appear in the context diagram.

Question22: What is diverging data flow?

A diverging data flow is a data flow in which the same data travels to two or more differentlocations. Diverging data flows occur infrequently and typically represent multiples part forms

that are sent to two or more recipients.


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Question23:What is functional primitive? What is leveling? What is purpose of reference

numbering technique?

A fuctional primitive is a process that consists of a single function and is not

exploded further.

Leveling is the DFD technique of representing the graphical model of and

information system first as a single process and then in greater and greater detailuntil the only processes are fuctional primitives.

Purpose Reference numbering technique is to tie together all data flow diagrams

in an orderly fashion. (is part of the leveling)

Question25: Which conventions are used in Data Flow Diagram?

The following rules must be applied when constructing diagrams:

Each context diagram must fit on one page

The process name in each context diagram should be the name of the information

system.

Use unique names within each set of symbols.

Avoid crossing lines, if at all possible Use abbreviated identifications when you are using a computerised data

dictionary.The main components of Data Flow Diagram are following:

Process

Data Flow

Data Store

External

Question26: What is the function of context diagram?

The context diagram is a data flow that shows the boundaries of the information system. The

context diagram is a top-level view of the information system.

Question27: What is the function of data flow diagrams in lower levels?DFD describes the information flow in the system. In lower levels, this function is detail the

information necessary for implementation of functions (process) in high level than more.

Question28: What is the function of each data flow in your system?

Data flow is used to describe the movement of information from one part of the system toanother. A data flow is represented graphically by an arrow into or out of a process.


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Question29: What is the function of each data store in your system?

Data store is used to model a collection of data packets at rest. A data store is representedgraphically by to parally by two paralel lines.

Question30:What is the relationship between data flow diagrams and your completedprogram?

DFD very importaint for completed program because: DFD will support 4 main activities:

Analysis: DFD is used to determine requirements of users.

Design: One of the strength of DFD is its simplicity and ease to understand to

analysts and users.

Documents: DFD is used to provide special description of requirements and system design.

Question 32: What is Normalization? Purpose of Normalization?

Normalization is the process by which you identify and correct inherent problems and

complexities in your record design. The normalization process involves three types of normal

forms: first normalization form (1NF), second normalization form (2NF), and thirdnormalization form (3NF).

Thepurpose of normalization isto reduce the chancesfor anomalies to occur in a database

Question 33: What are unnormalised records, 1NF, 2NF, 3NF?

Un-normalized form (UNF): is a table that contains one or more repeating groups.

First normalized form (1NF): A record is in first normal form if it does not contain a

repeating group. (To convert an UNF record which contains one or more repeating group to a

record in 1NF, you should remove the repeating group and expand the primary key to include thekey of the repeating group.)

Second normalized form (2NF): A record design is in 2NF if it is in 1NF and if all fieldsthat are not part of the primary key are dependent on the entire primary key. A 1NF record with aprimary key that is a single field that is already in 2NF. To convert a record to 2NF: First, for

each field in the primary key you create a separate record. Then crate additional separate records

for all combination of the primary key fields taken two at a time, three at a time and so on, untilyou finally crate a record with the entire original primary key.

Third normalize form (3NF): A record design is in 3NF if it is in 2NF and if no non key

field is dependent on another non key field. To convert to 3NF, remove all fields from the 2NF

record that depend on another non key field and place them into a new record with the other fieldas the primary key.

Question 34: What is an entity?Entity is a subject, a duty, or an event that has a significant meaning to the future system and is

displayed by a rectangle with round corner. Each entity has its own name. Entity type of a

system is defined base on the outcome of system function analyses.Entity can be a person, place, object, event, or concept about which we wish to store data.

Question 35: What is relationship?


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A relationship is a link or association between entities. Relationships are usually denoted by

verb phrases.

Question 36: What are the Primary Key, foreign key, alternate key and candidate key?

1. Primary Key:A primary key is used to uniquely identify each row in a table. It can either be part of the actual

record itself, or it can be an artificial field (one that has nothing to do with the actual record). A

primary key can consist of one or more fields on a table. When multiple fields are used as aprimary key, they are called a composite key.

Primary keys can be specified either when the table is created (using CREATE TABLE) or by

changing the existing table structure (using ALTER TABLE)2. Foreign Key:

A foreign key is a field (or fields) that points to the primary key of another table. The purpose of

the foreign key is to ensure referential integrity of the data. In other words, only values that are

supposed to appear in the database are permitted.

3.Alternate key:In the context of relational databases, an alternate key (or secondary key) is any candidate key

which is not selected to be the primary key (PK).4. Candidate key:

A candidate key is a combination of attributes that can be uniquely used to identify a database

record without any extraneous data. Each table may have one or more candidate keys. One of

these candidate keys is selected as the table primary key.

Question 37: What are 1: M, M: N, 1:1 relationship?

1: M relationship: One-to-many

One-to-many (also known as "to-many") relationships are often used when managing databases.

A one-to-many relationship occurs when one entity is related to many occurrences in another

entity.M: N relationship: Many-to-many

Many-to-many relationship, arrow in table A can have many matching rows in the table B, and

vice verse.You can such as a relationship by defining a third table, called a junction table, whose primary

key consist of the foreign keys from both table A and table B.

1:1 relationship: One-to-one

In a one- to- one relationship, a row in the table A can have no more than one matching row intable B, and vice verse.

A one to one relationship in created if both of the related columns are primary keys or have

unique constraints.This type of relationship is not common because most information related in the way would be

all in one table.

Question 38: Which data models for database do you know?

+ Hierarchical database models

+The network database models

+ Client Server database


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Question 41: What is a database? What is the purpose of database?

A collection of information organized in such a way that a computer program can quickly selectdesired pieces of data. Traditional databases are organized by fields, records, and files. Databases

are designed for three main purposes. These are to organize, store, and retrieve information as

efficiently and effectively as possible.


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Question 42: What is the purpose of data integrity rules?

Database integrity ensures that data entered into the database is accurate, valid, and consistent.

Question 43: What is the entity integrity rule?The entity integrity is an integrity rule which states that every table must have a primary key and

that the column or columns chosen to be the primary key should be unique and not null.

Question 44: What is the referential integrity rule?

Referential integrity is a property of data which, when satisfied, requires every value of oneattribute (column) of a relation (table) to exist as a value of another attribute in a different (or the

same) relation (table).