foreword
The following content is only the answers to the test sites that I need to memorize based on the real questions of the department-by-case cases of the year, which are convenient for personal recitation and memory use. It is convenient for text-to-speech, so the content is all pure text content, the following content is for reference only.
memorize content
FAST development method
The FAST development method includes four stages in the system analysis: initial research, problem analysis, demand analysis, and decision analysis.
First, the main tasks of FAST development in the system analysis preliminary research stage: 1. List problems and opportunities 2. Negotiate Preliminary scope of the project 3. Evaluate the value of the project 4. Plan the project schedule and budget 5. Report the project plan 2. The
main tasks of the FAST development system in the problem analysis stage: 1. Research problem areas 2. Analyze problems and opportunities 3. Analyze Business process 4. Formulate system improvement goals 5. Revise project plan 6. Report investigation results and suggestions
3. The main tasks of FAST development in the system requirements analysis stage: 1. Define requirements 2. Prioritize requirements 3. Modify project plan 4. Statement of communication requirements
4. The main tasks of FAST development in the decision-making analysis phase of the system: 1. Determine candidate solutions 2. Analyze candidate solutions 3. Compare candidate solutions 4. Modify project plan 5. Recommend a system
Feasibility of information system project development
It generally includes three aspects: possibility, effectiveness and necessity, and the three complement each other and are indispensable.
(1) Possibility includes the feasibility of technical, material, financial and personnel support;
(2) Effectiveness includes the economic and social benefits that can be brought by the implementation of the project;
(3) Necessity is more complicated, including social Environment, leadership willingness, personnel quality, cognitive level and other factors.
There are four aspects of information system project feasibility study content:
technical feasibility analysis, economic feasibility analysis, operating environment feasibility analysis and other aspects of feasibility analysis. Among them, the operating environment is the key to restricting the effectiveness of the information system in the user unit.
1. Factors to be considered in technical feasibility analysis: the risk of project development; the effectiveness of human resources; the possibility of technical capabilities; the availability of materials (products).
2. Economic feasibility analysis includes: expenditure analysis, income analysis, investment return analysis and sensitivity analysis.
3. Feasibility analysis of the operating environment needs to be carried out from the management system, management methods, rules and regulations, work habits, personnel quality (even including personnel's psychological endurance, enthusiasm for accepting new knowledge and skills, etc.) of the user unit (enterprise), data Resource accumulation, hardware (including system software) platform and other aspects are evaluated to determine whether the software system can run smoothly in the user unit after delivery.
4. Feasibility analysis of other aspects, such as legal feasibility, social feasibility and other aspects of feasibility analysis.
The feasibility of the software system is often tested here, and the content is basically similar.
Feasibility analysis of software system :
(1) Economic feasibility. It mainly evaluates the construction cost, operation cost and possible economic benefits of the project after the project is completed.
(2) Technical feasibility. The object of the research is the function and performance that the information system needs to realize, as well as the constraints of technical capabilities.
(3) Legal feasibility. It has a relatively broad content, and it needs to demonstrate the reality of information system construction from social factors such as policy, law, morality, and system.
(4) User feasibility. From the perspective of information system users, evaluate the feasibility of the system, including the administrative management and work system of the enterprise, the quality and training requirements of the users, etc.
design class
Identifying the design class is one of the important links in the object-oriented design process. The design class expresses the responsibility of the class, that is, the tasks undertaken by the class. The design class usually includes the following three types: ( 1 )
Entity class . Each entity in the entity class mapping requirements holds information that needs to be stored in a permanent storage, for example, employee information, leave application form.
(2) Control category . A control class is a class used to control the work of a use case, and is used to model the control behavior specific to one or several use cases. For example, submit a leave request, and approve a leave request.
(3) Boundary class . Boundary classes are used to encapsulate the flow of information or data flowing inside and outside a use case. For example, leave application page, leave approval form.
Common class relationships include:
(1) Association relationship . An association provides a structural relationship between objects of different classes, and it connects instances of multiple classes together over time. Associations reflect the relationship between object instances, not the relationship between two classes. The remaining relations concern descriptions of the classifiers themselves, not their instances.
(2) Dependency . Two classes A and B, if a change in B may cause a change in A, then class A is said to depend on class B. Dependencies can arise for various reasons, for example, one class sends a message to another class, one class is a data member of another class, one class is a certain operation parameter of another class, etc.
(3) Generalization relationship . The generalization relationship describes the relationship between a general thing and a special category in that thing, that is, the relationship between a parent category and a child category. The inheritance relationship is the anti-relationship of the generalization relationship, that is, the subclass inherits the parent class, and the parent class is the generalization of the subclass.
(4) Inheritance relationship . In essence, it is a generalization relationship. Inheritance is a mechanism by which different classes share properties and methods within a class hierarchy. The relationship between the parent class and the subclass is a general and special relationship. A parent class can have multiple subclasses, and these subclasses are special cases of the parent class.
(5) Aggregation relationship . Indicates the whole-part relationship between classes, which means that a "part" may belong to multiple "wholes" at the same time, and the life cycles of "parts" and "wholes" may be different . For example, a car and a wheel are an aggregation relationship. If the car is broken, the wheel can still be used; if the wheel is broken, it can be replaced.
(6) Combination relationship . Represents whole-part relationships between classes. The difference from the aggregation relationship is that the "part" in the composition relationship can only belong to one "whole", and the life cycle the same, the "part" is created with the creation of the "whole", and dies with the demise of the "whole". For example, a company contains multiple departments, and the relationship between them is a composition relationship. Once the company goes bankrupt, there is no department.
(7) Realize relationship . A realization relationship links a specification with a realization. An interface is a description of behavior rather than an implementation, while a class contains the structure of the implementation. One or more classes can implement an interface, and each class implements the operations in the interface.
Comparing Composition and Inheritance
1. Encapsulation:
Combination: Does not destroy encapsulation, loose coupling between the overall class and the partial class, relatively independent.
Inheritance: Encapsulation is broken, subclasses are tightly coupled with parent classes, and subclasses lack independence.
2, Dynamic combination:
combination: support dynamic combination.
Inheritance: Dynamic composition is not supported.
3. Create objects:
Combination: When creating an overall class, you need to create objects of all partial classes.
Inheritance: When creating a subclass object, there is no need to create a parent class object.
Theme database
The design requirements of the theme database:
(1) It should be designed to be as stable as possible, so that it can provide stable services for enterprise information resources in a long period of time.
(2) The logical structure of the subject database is required to be independent of the physical realization process of current computer hardware and software, so that the logical structure of the subject database can still be effective under the condition of continuous technological progress.
A subject database has the following basic characteristics:
(1) Oriented to business topics. A theme database is a business theme-oriented data organization store.
(2) Information sharing. The theme database is the denial of the databases that are "self-built and used" by each application system, and emphasizes the establishment of a shared database that is "co-constructed and shared" by each application system. Different application systems uniformly call the theme database.
(3) Enter the system one at a time. Thematic databases require research and analysis of data sources at all levels of enterprise management, emphasizing on-site data collection, on-site processing, use, and storage, as well as necessary transmission, aggregation, and centralized storage. The same data must enter the system once and at one place to ensure its accuracy, timeliness and completeness, but it can be used multiple times and at many places.
(4) Consists of basic tables. The subject database is composed of multiple data entities that meet the requirements of the basic table specification (satisfying 3NF).
SOA (Service-Oriented Architecture) Architecture
From the definition of the basic principles of software, SOA can be considered as a component model. It connects the different functional units of an application (called services) through well-defined interfaces and contracts between those services. The interface is defined in a neutral way, which is independent of the hardware platform, operating system and programming language of the service. This allows services built into various such systems to interact in a unified and common way.
In the architecture of SOA, various principles from object and component design are inherited. Such as encapsulation and self-containment etc. Design principles that ensure service flexibility, loose coupling, and reusability are also very important to the SOA architecture.
Services have common design principles as follows:
(1) Clearly defined interface
(2) Self-contained and modular
(3) Coarse-grained
(4) Loose coupling
(5) Interoperability, compatibility and policy statement
REST (Representational State Transfer) expresses state transfer, which is a Using HTTP and XML for Web communication technology can reduce the complexity of development and improve the scalability of the system. Its simplicity and lack of strict configuration files make it well isolated from SOAP, and REST fundamentally supports only a few operations (POST, GET, PUT, and DELETE), which apply to all information.
REST design concepts and guidelines:
(1) All things on the network are abstracted as resources
(2) Each resource corresponds to a unique resource identifier
(3) The resource is operated through a common connector interface
(4) The operation of the resource will not change the resource identifier
(5) All operations are stateless
cloud database
Cloud database refers to a database that is optimized or deployed in a virtual computing environment, which can realize the advantages of pay-as-you-go, expand-on-demand, high availability, and storage consolidation. According to the type of database, it is generally divided into relational database and non-relational database (NoSQL database).
The characteristics of cloud database include: fast instance creation, support for read-only instances, read-write separation, automatic failover, data backup, Binlog backup, SQL audit, access whitelist, monitoring and message notification, etc.
Advantages of the three-tier architecture
1. Good reusability, as long as the interface remains unchanged, it can be used elsewhere;
2. Good maintainability;
3. Good scalability, supporting incremental design;
4. After reasonable layering, the overall coupling of the system can be reduced, To achieve the effect of decoupling;
5. The content of the same logic and abstract level can be placed at the same level.