Author: saqibkhan

  • Software Quality Assurance in Software Engineering

    Introduction

    Software Quality Assurance in Software Engineering

    During the software development cycle, a software quality assurance engineer plays a pivotal role with their attention to detail concerning the product’s functionality and quality standards. These SQA experts are responsible for creating and implementing testing strategies to locate and remedy issues within software applications. Their work ensures that the errors, malfunctions, and discrepancies in software applications are adequately rectified, thus providing users with maximum satisfaction through a reliable interface.

    What is Quality?

    Quality defines to any measurable characteristics such as correctness, maintainability, portability, testability, usability, reliability, efficiency, integrity, reusability, and interoperability.

    There are two kinds of Quality:

    Software Quality Assurance in Software Engineering
    1. Quality of Design: Quality of Design refers to the characteristics that designers specify for an item. The grade of materials, tolerances, and performance specifications that all contribute to the quality of design.
    2. Quality of conformance: Quality of conformance is the degree to which the design specifications are followed during manufacturing. Greater the degree of conformance, the higher is the level of quality of conformance.

    Quality Assurance

    Quality Assurance is the preventive set of activities that provide greater confidence that the project will be completed successfully.

    Quality Assurance focuses on how the engineering and management activity will be done?

    As anyone is interested in the quality of the final product, it should be assured that we are building the right product.

    It can be assured only when we do inspection & review of intermediate products, if there are any bugs, then it is debugged. This quality can be enhanced.

    Importance of Quality

    We would expect the quality to be a concern of all producers of goods and services. However, the distinctive characteristics of software and in particular its intangibility and complexity, make special demands.

    Increasing criticality of software: The final customer or user is naturally concerned about the general quality of software, especially its reliability. This is increasing in the case as organizations become more dependent on their computer systems and software is used more and more in safety-critical areas. For example, to control aircraft.

    The intangibility of software: This makes it challenging to know that a particular task in a project has been completed satisfactorily. The results of these tasks can be made tangible by demanding that the developers produce ‘deliverables’ that can be examined for quality.

    Accumulating errors during software development: As computer system development is made up of several steps where the output from one level is input to the next, the errors in the earlier? deliverables? will be added to those in the later stages leading to accumulated determinable effects. In general, the later in a project that an error is found, the more expensive it will be to fix. In addition, because the number of errors in the system is unknown, the debugging phases of a project are particularly challenging to control.

    Software Quality Assurance

    Software quality assurance is a planned and systematic plan of all actions necessary to provide adequate confidence that an item or product conforms to establish technical requirements.

    A set of activities designed to calculate the process by which the products are developed or manufactured.

    Implementation of Software Quality Assurance

    In terms of providing effective software quality assurance or SQA, construction of an extensive system that tracks each phase of development is equally important as maintaining pre-established standards. In order to properly implement SQA into a project, follow these procedures.

    1. Specify the goals and objectives for quality

    Establishing a clear definition of quality for your project is the first step. Establish SMART goals-specific measurable achievable relevant and time-bound-that complement the needs of your clients and the goals of your company.

    2. Create a plan for SQA

    Make a SQA plan that details the methods for ensuring quality throughout the project. The following should be part of this plan:

    • Roles and responsibilities: Assigning team members to specific quality assurance positions.
    • Standards and Procedures: Defining coding, review, and documentation standards.
    • Tools and Resources: Identifying tools for defect tracking, test automation, and document management.

    3. Establish Quality Metrics

    Establish metrics to gauge the SQA process efficacy. Defect density code coverage by tests customer issue incidents etc. are a few examples. These metrics will be used to track the success and advancement of quality assurance initiatives.

    4. Perform Formal Technical Reviews

    To find flaws early in the development process conduct inspections and peer reviews at different points. Test plans design documents code and requirements can all be subject to reviews.

    5. Implement Testing Strategies

    Create a thorough testing plan that addresses the following testing standards:

    • Unit Testing: Individual components are tested to ensure their correctness.
    • Integration tests: Ensure that software components work together properly.
    • System Testing: Ensure that the system meets all of the defined standards.
    • Acceptance Testing: Running tests to confirm that the system is ready for production.

    6. Ensure Compliance with Standards

    Throughout the development process follow applicable industry standards (e. g. ISO/IEC 25010 for software quality or industry-specific compliance standards).

    7. Utilize Automation Where Possible

    If you want to increase efficiency and consistency automate labour-intensive and repetitive tasks like build deployments regression testing and some performance testing.

    8. Train and Develop Skills

    Train team members on the newest technologies tools and approaches for quality assurance on a regular basis. The team’s capacity to recognize and address quality problems can be greatly improved by investing in skill development.

    9. Continuous Process Improvement

    Continue to assess the SQA process efficacy and make necessary adjustments. Determine your areas of weakness and take corrective action using the quality metrics that were gathered.

    10. Risk control

    Determine possible hazards that might affect the software’s quality and create plans to reduce them. Prioritizing SQA efforts can be aided by routine risk assessments.

    SQA Encompasses

    • A quality management approach
    • Effective Software engineering technology (methods and tools)
    • Formal technical reviews that are tested throughout the software process
    • A multitier testing strategy
    • Control of software documentation and the changes made to it.
    • A procedure to ensure compliances with software development standards
    • Measuring and reporting mechanisms.

    SQA Activities

    Software quality assurance is composed of a variety of functions associated with two different constituencies ? the software engineers who do technical work and an SQA group that has responsibility for quality assurance planning, record keeping, analysis, and reporting.

    Following activities are performed by an independent SQA group:

    1. Prepares an SQA plan for a project: The program is developed during project planning and is reviewed by all stakeholders. The plan governs quality assurance activities performed by the software engineering team and the SQA group. The plan identifies calculation to be performed, audits and reviews to be performed, standards that apply to the project, techniques for error reporting and tracking, documents to be produced by the SQA team, and amount of feedback provided to the software project team.
    2. Participates in the development of the project’s software process description: The software team selects a process for the work to be performed. The SQA group reviews the process description for compliance with organizational policy, internal software standards, externally imposed standards (e.g. ISO-9001), and other parts of the software project plan.
    3. Reviews software engineering activities to verify compliance with the defined software process: The SQA group identifies, reports, and tracks deviations from the process and verifies that corrections have been made.
    4. Audits designated software work products to verify compliance with those defined as a part of the software process: The SQA group reviews selected work products, identifies, documents and tracks deviations, verify that corrections have been made, and periodically reports the results of its work to the project manager.
    5. Ensures that deviations in software work and work products are documented and handled according to a documented procedure: Deviations may be encountered in the project method, process description, applicable standards, or technical work products.
    6. Records any noncompliance and reports to senior management: Non- compliance items are tracked until they are resolved.

    Advantages of SQA

    1. High-quality software is produced by SQA.
    2. A well-designed application saves money and time.
    3. SQA helps to improve reliability.
    4. SQA is advantageous when there is no maintenance for an extended period of time.
    5. Commercial software of superior quality boosts a company’s market share.
    6. Enhancing the software development process.
    7. Enhances the software’s quality.
    8. The cost of maintenance is reduced. Your business can move on to the next big thing and forget about the release if it is done correctly the first time. If you release a product with persistent problems your company will become mired in an expensive time-consuming and never-ending cycle of repairs.

    Drawbacks of SQA

    The quality assurance process has several drawbacks:

    1. Cost: Adding resources to improve the product is one of them the more resources added the less money is spent. Time-consuming: Project deployment and testing take longer which delays the project.
    2. Administrative overhead: SQA procedures may result in the need for reporting documentation and quality metrics tracking. Particularly for smaller projects the advantages may occasionally be outweighed by this extra administrative load.
    3. Resource-intensive: SQA calls for knowledgeable staff members who are knowledgeable about testing techniques instruments and quality control procedures. Such talent can be costly and difficult to acquire and retain.
    4. Opposition to Change: Because they believe that SQA procedures are superfluous or bureaucratic some team members may be against their adoption. An organization’s ability to implement and benefit from quality assurance procedures may be hampered by this resistance.
    5. Not Foolproof: Software may still have flaws or vulnerabilities in spite of rigorous testing and quality assurance procedures. The complete removal of all defects or problems in software products cannot be ensured by SQA.
    6. Complexity: Especially in large-scale projects with numerous stakeholder’s dependencies and integration points SQA procedures can be complicated. Careful planning and coordination are necessary to manage the complexity of quality assurance tasks.

    Quality Assurance v/s Quality control

    Quality AssuranceQuality Control
    Quality Assurance (QA) is the set of actions including facilitation, training, measurement, and analysis needed to provide adequate confidence that processes are established and continuously improved to produce products or services that conform to specifications and are fit for use.Quality Control (QC) is described as the processes and methods used to compare product quality to requirements and applicable standards, and the actions are taken when a nonconformance is detected.
    QA is an activity that establishes and calculates the processes that produce the product. If there is no process, there is no role for QA.QC is an activity that demonstrates whether or not the product produced met standards.
    QA helps establish processQC relates to a particular product or service
    QA sets up a measurement program to evaluate processesQC verified whether particular attributes exist, or do not exist, in a explicit product or service.
    QA identifies weakness in processes and improves themQC identifies defects for the primary goals of correcting errors.
    Quality Assurance is a managerial tool.Quality Control is a corrective tool.
    Verification is an example of QA.Validation is an example of QC.

    Frequently Asked Questions – FAQs

    1. What does software quality assurance mean?

    Answer: SQA is a collection of organized and methodical development tasks meant to guarantee compliance with established standards and specifications. In order to produce software products of the highest quality it includes tasks like testing bug tracking code reviews and process improvements.

    2. What is the process for software quality assurance?

    Answer: The SQA process uses steps like planning creating test cases conducting tests and reporting problems to systematically guarantee the quality of software products. By helping to find and fix problems it guarantees that software meets specifications and operates as planned.

    3. Why is quality assurance used in software?

    Answer: SQA is used to ensure that software products meet quality standards reduce errors and boost customer satisfaction. It improves overall program dependability and efficiency detects issues and verifies requirement compliance. By reducing the risks connected with broken programs SQA encourages efficient software development.

    4. What is the purpose of software quality assurance?

    Answer: SQA improves product reliability and prevents defects by using systematic processes to ensure that software satisfies predetermined standards and requirements.

    5. Software quality assurance activities: what are they?

    Answer: To guarantee software quality throughout the development lifecycle SQA activities include planning creating standards running tests monitoring errors and keeping records.

  • SCM Process

    It uses the tools which keep that the necessary change has been implemented adequately to the appropriate component. The SCM process defines a number of tasks:

    • Identification of objects in the software configuration
    • Version Control
    • Change Control
    • Configuration Audit
    • Status Reporting
    SCM Process

    Identification

    Basic Object: Unit of Text created by a software engineer during analysis, design, code, or test.

    Aggregate Object: A collection of essential objects and other aggregate objects. Design Specification is an aggregate object.

    Each object has a set of distinct characteristics that identify it uniquely: a name, a description, a list of resources, and a “realization.”

    The interrelationships between configuration objects can be described with a Module Interconnection Language (MIL).

    Version Control

    Version Control combines procedures and tools to handle different version of configuration objects that are generated during the software process.

    Clemm defines version control in the context of SCM: Configuration management allows a user to specify the alternative configuration of the software system through the selection of appropriate versions. This is supported by associating attributes with each software version, and then allowing a configuration to be specified [and constructed] by describing the set of desired attributes.

    Change Control

    James Bach describes change control in the context of SCM is: Change Control is Vital. But the forces that make it essential also make it annoying.

    We worry about change because a small confusion in the code can create a big failure in the product. But it can also fix a significant failure or enable incredible new capabilities.

    We worry about change because a single rogue developer could sink the project, yet brilliant ideas originate in the mind of those rogues, and

    A burdensome change control process could effectively discourage them from doing creative work.

    A change request is submitted and calculated to assess technical merit; potential side effects, the overall impact on other configuration objects and system functions, and projected cost of the change.

    The results of the evaluations are presented as a change report, which is used by a change control authority (CCA) – a person or a group who makes a final decision on the status and priority of the change.

    The “check-in” and “check-out” process implements two necessary elements of change control-access control and synchronization control.

    Access Control governs which software engineers have the authority to access and modify a particular configuration object.

    Synchronization Control helps to ensure that parallel changes, performed by two different people, don’t overwrite one another.

    Configuration Audit

    SCM audits to verify that the software product satisfies the baselines requirements and ensures that what is built and what is delivered.

    SCM audits also ensure that traceability is maintained between all CIs and that all work requests are associated with one or more CI modification.

    SCM audits are the “watchdogs” that ensures that the integrity of the project’s scope is preserved.

    Status Reporting

    Configuration Status reporting (sometimes also called status accounting) providing accurate status and current configuration data to developers, testers, end users, customers and stakeholders through admin guides, user guides, FAQs, Release Notes, Installation Guide, Configuration Guide, etc.

  • Software Configuration Management in Software Engineering

    When we develop software, the product (software) undergoes many changes in their maintenance phase; we need to handle these changes effectively.

    Several individuals (programs) works together to achieve these common goals. This individual produces several work product (SC Items) e.g., Intermediate version of modules or test data used during debugging, parts of the final product.

    The elements that comprise all information produced as a part of the software process are collectively called a software configuration.

    As software development progresses, the number of Software Configuration elements (SCI’s) grow rapidly.

    These are handled and controlled by SCM. This is where we require software configuration management.

    A configuration of the product refers not only to the product’s constituent but also to a particular version of the component.

    Therefore, SCM is the discipline which

    • Identify change
    • Monitor and control change
    • Ensure the proper implementation of change made to the item.
    • Auditing and reporting on the change made.

    Configuration Management (CM) is a technic of identifying, organizing, and controlling modification to software being built by a programming team.

    The objective is to maximize productivity by minimizing mistakes (errors).

    CM is used to essential due to the inventory management, library management, and updation management of the items essential for the project.

    Why do we need Configuration Management?

    Multiple people are working on software which is consistently updating. It may be a method where multiple version, branches, authors are involved in a software project, and the team is geographically distributed and works concurrently. It changes in user requirements, and policy, budget, schedules need to be accommodated.

    Importance of SCM

    It is practical in controlling and managing the access to various SCIs e.g., by preventing the two members of a team for checking out the same component for modification at the same time.

    It provides the tool to ensure that changes are being properly implemented.

    It has the capability of describing and storing the various constituent of software.

    SCM is used in keeping a system in a consistent state by automatically producing derived version upon modification of the same component.

  • Functional and Non-Functional Requirements in Software Engineering

    In software development and systems engineering, functional requirements are the intended functions of a program or system. In systems engineering, the systems might be either software-driven electronics or software-driven hardware. The multidisciplinary engineering discipline of requirements analysis, sometimes referred to as requirements engineering, focuses on the design and upkeep of complex systems and includes functional requirements. To ensure that the design is sufficient to achieve the intended result and that the final product fulfills the design’s potential in order to satisfy user expectations, functional requirements specify the intended end function of a system functioning under typical conditions.

    In this tutorial, we will discuss two important terms used in software engineering that are functional requirements and non-functional requirements, along with the comparison between them. Understanding the difference between both terms helps to ensure that the delivered product meets the expectations of the client.

    So, without more delay, let’s start the topic.

    Functional Requirements

    Functional requirements define a function that a system or system element must be qualified to perform and must be documented in different forms. The functional requirements describe the behavior of the system as it correlates to the system’s functionality.

    Functional requirements should be written in a simple language, so that it is easily understandable. The examples of functional requirements are authentication, business rules, audit tracking, certification requirements, transaction corrections, etc.

    These requirements allow us to verify whether the application provides all functionalities mentioned in the application’s functional requirements. They support tasks, activities, user goals for easier project management.

    There are a number of ways to prepare functional requirements. The most common way is that they are documented in the text form. Other formats of preparing the functional requirements are use cases, models, prototypes, user stories, and diagrams.

    Importance of Functional Requirements

    Since they specify the precise functions that the system must have, functional requirements are essential. The functional requirements are beneficial in the following way:

    • During the guiding phase, developers create and develop system features under the direction of functional systems.
    • To support the testing, System-testing procedures are based on functional requirements, which guarantee that the system operates as intended.
    • In order to meet stakeholders’ expectations: By making a system’s features more clear, functional requirements help the development team meet stakeholder expectations.

    Functional Requirements Documentation

    Usually, functional requirements are recorded using one of the forms listed below:

    • Use cases: A use case describes how the user (or system) interacts with the system to complete specific activities.
    • User story: User stories explain how a system’s user imagines its capabilities. “As a [user], I want to [perform a task] so that [I could achieve my goal].” is the format they utilize.
    • Specifications of the system: These are incredibly thorough papers that outline every task the system is expected to perform in relation to inputs, outputs, procedures, and error control.

    Non-Functional Requirements: What Are They?

    Unexpectedly, non-functional requirements (NFRs) outline the standards for how the system must operate. Non-functional specifications cover nearly all significant functional features of the system, such as how a particular set of activities or services should be carried out, in contrast to functional requirements, which focus on what the system should perform. In any case, they outline the system’s quality qualities, including usability, security, scalability.Non-functional requirements outline the features of the system’s operation, guaranteeing that it will work in accordance with stakeholders’ and users’ expectations for its performance and behavior.

    Non-Functional Requirements Examples

    The non-functional criteria determine the quality and performance of a good system. Among them are:

    1. Performance: A system may accommodate 1,000 users at once without seeing a significant decline in performance.
    2. Scalability: The system must allow for horizontal scaling if it is to accommodate ever-increasing user and transaction volumes.
    3. Security: In compliance with industry standards, all data must be secured while being sent (TLS 1.2).
    4. Availability: The system must have an annual uptime of at least 99.9%.
    5. Usability: The interface is easy to use, requiring no more than three clicks to access any significant function.
    6. Compliance: The system shall handle personal data in accordance with the General Data Protection Regulation (GDPR).
    7. Maintainability: Because the code is well-written and adheres to a sound design, it makes upgrading and maintenance simple.

    Non-Functional Requirements Importance

    Non-functional requirements are crucial since they influence how well the system performs in different scenarios. As a result, a system guarantees that it satisfies commercial and regulatory requirements while offering a positive user experience.

    1. Set quality standard levels: NFRs specify the performance requirements that the system must fulfill in order to guarantee the dependable, safe, and seamless functioning of your program.
    2. Guide architectural choices: Non-functional requirements influence important system-wide architectural and design decisions, such the selection of platforms and technologies.
    3. Boost user happiness: NFRs raise user satisfaction and the entire user experience by tackling usability, performance, and security concerns.

    Non-Functional Requirements Documentation

    Usually, non-functional needs are recorded in:

    • Service Level Agreements (SLAs): These specify the service levels, such as uptime, response times, or other performance indicators, that the system must provide.
    • Quality Attribute Scenarios: These describe the system’s quality characteristics and the performance results that are anticipated in specific circumstances (such as while awaiting a spike in traffic).

    The technical and architectural requirements that the system must fulfill are outlined in the Technical Architecture and Design Document. These requirements cover scalability, performance, and security.

    Important Distinctions Between Non-Functional and Functional Requirements

    The difference between function and non-functional requirements are as follows:

    Non-Functional RequirementsFunctional Requirements
    a. Explains how the system ought to operate.a. Outlines the requirements for the system.
    b. Pay attention to system quality criteria, such as security and performance.b. Data processing, user authentication, and reporting.
    c. Performance, availability, security, and scalability.c. Outlines the requirements for the system.
    d. Evaluated using parameters such as load capacity, speed, and uptime.d. Frequently quantifiable in terms of procedures or actions.
    e. Effects on system dependability, efficiency, and user pleasure.e. Direct effect on business logic and user functionality.
    f. Top priority to guarantee the system runs effectively.f. Determining system behavior is a top priority.

    The Significance of Both Functional and Non-Functional Requirements

    1. Equitable Growth: A system that just uses functional requirements would work as intended, but it wouldn’t scale effectively, be secure, or operate at a level that end users would find acceptable. To satisfy users’ and businesses’ expectations, a system must satisfy both functional and non-functional needs.
    2. System Design That Works: If non-functional needs are not met, the system may still be functionally accurate but have decreased security or performance, which is often unacceptable. For instance, a website may perform flawlessly when displaying product details (a functional need) yet malfunction when 1000 individuals attempt to access it at once (a non-functional requirement). A developer may be able to create software that is secure, expandable, robust, and performs better by taking into account both of these kinds of requirements. This will increase user satisfaction and further lower the number of system incidents.

    The Best Methods for Managing Functional and Non-Functional Needs

    1. Open and honest communication with interested parties

    Effective communication with the stakeholders is the first step towards successfully collecting both functional and non-functional needs. To write a comprehensive request, it is crucial to understand what the user, company owner, and technical team desire.

    2. Set Needs in Order of Priority

    Not every necessity is equally important. To assist steer development decisions and prevent scope creep, functional and non-functional requirements should be ranked according to user demands, technological viability, and business value.

    3. Make Use of Organized Documentation

    Create documentation that accurately reflects both kinds of criteria. A more effective method of monitoring requirements updates and modifications during the course of the project is to use organized templates and review boards, such those found in design system documentation.

    4. Frequent Validation and Testing

    Both functional and non-functional attributes must be regularly tested. While performance testing will determine whether the system satisfies the intended non-functional requirements of speed, reliability, and scalability, functional testing guarantees the system will operate as intended.

    5. Examine and Modify the Needs

    As development moves further, review the requirements to make sure they remain reasonable and attainable. Continuous evaluation and modification are necessary because change might occur within user expectations, company goals, and changing elements.

  • Entity-Relationship Diagram (ERD) in Software Engineering

    ER-modeling is a data modeling method used in software engineering to produce a conceptual data model of an information system. Diagrams created using this ER-modeling method are called Entity-Relationship Diagrams or ER diagrams or ERDs.

    Purpose of ERD

    • The database analyst gains a better understanding of the data to be contained in the database through the step of constructing the ERD.
    • The ERD serves as a documentation tool.
    • Finally, the ERD is used to connect the logical structure of the database to users. In particular, the ERD effectively communicates the logic of the database to users.

    Components of an ER Diagrams

    Entity-Relationship Diagrams

    1. Entity

    An entity can be a real-world object, either animate or inanimate, that can be merely identifiable. An entity is denoted as a rectangle in an ER diagram. For example, in a school database, students, teachers, classes, and courses offered can be treated as entities. All these entities have some attributes or properties that give them their identity.

    Entity Set

    An entity set is a collection of related types of entities. An entity set may include entities with attribute sharing similar values. For example, a Student set may contain all the students of a school; likewise, a Teacher set may include all the teachers of a school from all faculties. Entity set need not be disjoint.

    Entity-Relationship Diagrams

    2. Attributes

    Entities are denoted utilizing their properties, known as attributes. All attributes have values. For example, a student entity may have name, class, and age as attributes.

    There exists a domain or range of values that can be assigned to attributes. For example, a student’s name cannot be a numeric value. It has to be alphabetic. A student’s age cannot be negative, etc.

    Entity-Relationship Diagrams

    There are four types of Attributes:

    1. Key attribute
    2. Composite attribute
    3. Single-valued attribute
    4. Multi-valued attribute
    5. Derived attribute

    1. Key attribute: Key is an attribute or collection of attributes that uniquely identifies an entity among the entity set. For example, the roll_number of a student makes him identifiable among students.

    Entity-Relationship Diagrams

    There are mainly three types of keys:

    1. Super key: A set of attributes that collectively identifies an entity in the entity set.
    2. Candidate key: A minimal super key is known as a candidate key. An entity set may have more than one candidate key.
    3. Primary key: A primary key is one of the candidate keys chosen by the database designer to uniquely identify the entity set.

    2. Composite attribute: An attribute that is a combination of other attributes is called a composite attribute. For example, In student entity, the student address is a composite attribute as an address is composed of other characteristics such as pin code, state, country.

    Entity-Relationship Diagrams

    3. Single-valued attribute: Single-valued attribute contain a single value. For example, Social_Security_Number.

    4. Multi-valued Attribute: If an attribute can have more than one value, it is known as a multi-valued attribute. Multi-valued attributes are depicted by the double ellipse. For example, a person can have more than one phone number, email-address, etc.

    Entity-Relationship Diagrams

    5. Derived attribute: Derived attributes are the attribute that does not exist in the physical database, but their values are derived from other attributes present in the database. For example, age can be derived from date_of_birth. In the ER diagram, Derived attributes are depicted by the dashed ellipse.

    Entity-Relationship Diagrams
    Entity-Relationship Diagrams

    3. Relationships

    The association among entities is known as relationship. Relationships are represented by the diamond-shaped box. For example, an employee works_at a department, a student enrolls in a course. Here, Works_at and Enrolls are called relationships.

    Entity-Relationship Diagrams

    Relationship set

    A set of relationships of a similar type is known as a relationship set. Like entities, a relationship too can have attributes. These attributes are called descriptive attributes.

    Degree of a relationship set

    The number of participating entities in a relationship describes the degree of the relationship. The three most common relationships in E-R models are:

    1. Unary (degree1)
    2. Binary (degree2)
    3. Ternary (degree3)

    1. Unary relationship: This is also called recursive relationships. It is a relationship between the instances of one entity type. For example, one person is married to only one person.

    Entity-Relationship Diagrams

    2. Binary relationship: It is a relationship between the instances of two entity types. For example, the Teacher teaches the subject.

    Entity-Relationship Diagrams

    3. Ternary relationship: It is a relationship amongst instances of three entity types. In fig, the relationships “may have” provide the association of three entities, i.e., TEACHER, STUDENT, and SUBJECT. All three entities are many-to-many participants. There may be one or many participants in a ternary relationship.

    In general, “n” entities can be related by the same relationship and is known as n-ary relationship.

    Entity-Relationship Diagrams

    Cardinality

    Cardinality describes the number of entities in one entity set, which can be associated with the number of entities of other sets via relationship set.

    Types of Cardinalities

    1. One to One: One entity from entity set A can be contained with at most one entity of entity set B and vice versa. Let us assume that each student has only one student ID, and each student ID is assigned to only one person. So, the relationship will be one to one.

    Entity-Relationship Diagrams

    Using Sets, it can be represented as:

    Entity-Relationship Diagrams

    2. One to many: When a single instance of an entity is associated with more than one instances of another entity then it is called one to many relationships. For example, a client can place many orders; a order cannot be placed by many customers.

    Entity-Relationship Diagrams

    Using Sets, it can be represented as:

    Entity-Relationship Diagrams

    3. Many to One: More than one entity from entity set A can be associated with at most one entity of entity set B, however an entity from entity set B can be associated with more than one entity from entity set A. For example – many students can study in a single college, but a student cannot study in many colleges at the same time.

    Entity-Relationship Diagrams

    Using Sets, it can be represented as:

    Entity-Relationship Diagrams

    4. Many to Many: One entity from A can be associated with more than one entity from B and vice-versa. For example, the student can be assigned to many projects, and a project can be assigned to many students.

    Entity-Relationship Diagrams

    Using Sets, it can be represented as:

    Entity-Relationship Diagrams
  • Data Dictionaries

    A data dictionary is a file or a set of files that includes a database’s metadata. The data dictionary hold records about other objects in the database, such as data ownership, data relationships to other objects, and other data. The data dictionary is an essential component of any relational database. Ironically, because of its importance, it is invisible to most database users. Typically, only database administrators interact with the data dictionary.

    The data dictionary, in general, includes information about the following:

    • Name of the data item
    • Aliases
    • Description/purpose
    • Related data items
    • Range of values
    • Data structure definition/Forms

    The name of the data item is self-explanatory.

    Aliases include other names by which this data item is called DEO for Data Entry Operator and DR for Deputy Registrar.

    Description/purpose is a textual description of what the data item is used for or why it exists.

    Related data items capture relationships between data items e.g., total_marks must always equal to internal_marks plus external_marks.

    Range of values records all possible values, e.g. total marks must be positive and between 0 to 100.

    Data structure Forms: Data flows capture the name of processes that generate or receive the data items. If the data item is primitive, then data structure form captures the physical structures of the data item. If the data is itself a data aggregate, then data structure form capture the composition of the data items in terms of other data items.

    The mathematical operators used within the data dictionary are defined in the table:

    NotationsMeaning
    x=a+bx includes of data elements a and b.
    x=[a/b]x includes of either data elements a or b.
    x=a xincludes of optimal data elements a.
    x=y[a]x includes of y or more occurrences of data element a
    x=[a]zx includes of z or fewer occurrences of data element a
    x=y[a]zx includes of some occurrences of data element a which are between y and z.
    Data Dictionaries
  • Data Flow Diagram (DFD) in Software Engineering

    A data flow diagram (DFD) is a visual or graphical depiction that describes how a business moves data using a standard set of symbols and notations. A formal technique, such as the Structured Systems Analysis and Design Method (SSADM), frequently includes them. Although DFDs may appear to be similar to flow charts or Unified Modeling Language (UML) on the surface, they are not intended to depict specifics of program logic.

    Data Flow Diagrams

    What is the purpose of data flow diagrams?

    DFDs simplify the illustration of applications’ business needs by employing a graphical or visual depiction of the information flow and process step sequence instead of a textual description. They initially record the outcomes of business analysis before being utilized throughout the full development process. The depiction is then improved to demonstrate how data travels through and is altered by application flows. There are examples of both automated and manual procedures.

    What is the history of data flow diagrams?

    UMLs came after DFDs, which made their debut in software engineering in the late 1970s. The data flow graph computation models of David Martin and Gerald Estrin of the University of California, Los Angeles, served as the inspiration for the book Structured Design, which was published by computer experts Larry Constantine and Ed Yourdon and popularized DFDs. Object-oriented design, a significant paradigm change in software engineering that is still widely used today, was brought about by the concept of structured design. Computing specialists Chris Gane, Trish Sarson, and Tom DeMarco supplied the symbols and notations that became the norm in the DFD approach.

    Those early DFDs revolutionized software engineering, software development, and business processes. By defining workflows, identifying accessible data storage, and connecting system design to the activities the systems supported, diagramming the data flow through a data processing system helped to make sense of the data flow via business processes themselves.

    Data flow diagram Rules

    The majority of data flow diagrams adhere to these fundamental guidelines:

    1. The type of data being transferred is identified by a short, descriptive text label attached to each data flow.
    2. A succinct verb phrase describing the data transformation being carried out is used to identify each procedure.
    3. A term or noun phrase describing the kind of data and storage is attached to each data store.
    4. There is at least one input and one output for each process and data storage.
    5. External entities cannot be directly attached to data repositories.
    6. Data from outside sources cannot be sent straight to a data store, but it may be sent to a process.
    7. Data flows do not intersect for the sake of clarity.

    Data flow Diagram Components

    A DFD consists of the following four major parts:

    1. External entities
    2. Processes
    3. Data stores
    4. Data flows
    Data Flow Diagrams

    External entities

    These are where the data flow in a DFD begins and ends. External entities are positioned on the borders of a DFD to depict the entry and output of data to the entire system or process. A person, group, or system might be considered an external entity. In a DFD that simulates the process of making a purchase and obtaining a sales receipt, for instance, a customer can be an external entity. Terminators, actors, sources, and sinks are other names for external entities.

    Processes

    Activities that alter or transform data are called processes. Calculation, sorting, validation, redirection, and any other change necessary to move that section of the data flow forward might be included in these operations. For instance, a procedure that takes place during a customer’s purchase of DFD is credit card payment verification.

    Data stores

    In a DFD, data is kept for eventual use. A data store might represent databases, papers, files, or any other type of data storage repository. A product inventory database, a client address database, and a delivery schedule spreadsheet are a few examples of the data stored in a product fulfilment DFD.

    Data flows

    The paths that information takes when moving between external entities, processes, and data repositories are known as data flows. A data flow, for instance, would link a user inputting login information with an authentication gateway in an e-commerce DFD.

    What distinguishes a physical DFD from a logical DFD?

    Logical DFDs use rather abstract language to depict logical information flows. This implies that they will provide broad systems, procedures, and activities but not specifics about the technology. Physical DFDs display more physical information flow details, especially those pertaining to databases, applications, and information systems. Additionally, they frequently contain additional features to more accurately illustrate the flow of information, the actions being conducted on or with the data, and the resources involved in those activities.

    There are several logical and physical explanations for DFDs. Line organizations and enterprise architects often utilize logical DFDs and display fewer details on physical DFDs. Development teams, on the other hand, are more inclined to employ physical DFDs than logical ones.

    Which notations and symbols are used in DFDs?

    The concepts and symbols used in DFD differ depending on the methodological model used. Although it is not advised, certain groups have developed their own conventions.

    Data Flow Diagrams

    Various DFD notations consist of the following:

    • Sarson and Gane
    • DeMarco and Yourdon
    • SSADM
    • DFDs can make use of UML, which is frequently used to map software architecture.

    Every DFD concept stands for the following:

    • Outside parties: Data comes into or goes out of the system under description.
    • Movements: Describe the flow of data into, out of, and within the system under description.
    • Shops: locations where data is kept or stored, usually databases or database tables.
    • Procedures: Convert data.

    Various DFD approaches employ distinct symbol conventions. Technologists who are unfamiliar with a methodology may find it challenging to understand the DFDs due to the significant variations and diverging symbol rules.

    In the Gane and Sarson notation, for instance, processes have rounded corners, whereas entities are square-cornered boxes. In the Yourdon and DeMarco technique, processes are circles, whereas entities have square corners. The Gane and Sarson convention is nearly inverted in the SSADM approach. While the stores in De Marco and Yourdon are shown as parallel lines, every other methodology employs a different depiction. This is why it’s critical for a company to choose and adhere to a methodology and symbology.

    Which DFD layers and levels are there?

    In DFDs, levels or layers are used to depict increasing levels of system or process information. Among these levels are the following:

    • Level 0: The topmost level, also referred to as a context diagram, provides a straightforward, high-level perspective of the system being shown.
    • Level 1: Although it includes more information and subprocesses, this is still a rather general picture of the system.
    • Level 2: Continue to deconstruct subprocesses as necessary and provide much more depth.
    • Level 3: Although this degree of detail is rare, it can be useful for representing complicated systems.

    Although more layers are theoretically feasible, they are rarely employed and would probably indicate more detail than a data flow diagram would often show.

    How is a data flow diagram made?

    The following is a simple summary of the procedures to produce a DFD, although it may vary depending on the program used:

    Step 1: Select a system or process to the diagram.

    Step 2: After choosing the relevant interests, group them into external entities, flows, processes, and storage.

    Step 3: Use simple connections to illustrate a Level 0 context diagram.

    Step 4: Make more intricate Level 1 diagrams with linked flows, stores, extra processes, and external entities that branch off of the context diagram’s processes.

    Step 5: Repeat as often as needed and with as much detail as needed.

    Step 6: It’s critical to review the diagram regularly at every level to ensure that no processes or flows are missing or superfluous.

    What kinds of DFDs are there?

    Documents or lessons pertaining to a single approach are the greatest examples of DFDs. It might be challenging to understand the structure and visuals of example DFDs when they are reviewed without the framework of a methodology. Unlike flow charts or UML, which show software flows or software architecture, the majority of DFD examples show a business or functional view of a process.

    An illustration of a school’s culinary curriculum utilizing the Gane and Sarson technique may be found below.

    Which tools are available to create a DFD?

    Although DFDs can be drawn by hand, this is rarely done outside of ad hoc discussions. Graphics or presentation tools, especially those that allow for the development of custom symbols, can be used to produce DFDs. The usual necessity of such tools to select a fixed page size, however, makes this restrictive for the majority of DFD users.

    Specialized DFD tools, which are occasionally combined with additional characteristics related to the particular approach being employed, are utilized to construct the majority of DFDs. Numerous tools, both open-source and proprietary, are available. DFDs may also be created with cloud-hosted technologies. It’s crucial to choose a tool that complements the methodology to be employed because many of these are linked to certain approaches. An organization should think about using a standard tool since import and export capabilities may be restricted across different tools.

    The following are some instances of DFD tools:

    1. Canva
    2. ConceptDraw
    3. Creately
    4. Lucidchart from Lucid Software Inc
    5. Miro
    6. SmartDraw
    7. Venngage
    8. Visual Paradigm
    9. Wondershare EdrawMax from Edraw

    Advantages of DFDs

    DFDs provide the following advantages:

    1. A clearer image: A DFD offers an understandable visual depiction of the flow of data inside a system or process.
    2. Improved comprehension: A better comprehension of the process is encouraged, and discoveries may be sparked by a DFD’s visual depiction of what happens to data inside a process.
    3. Better connections between data resources: The DFD format makes it easier to comprehend and manage data storage resource identification, batch and real-time operations, and their interconnections.
    4. Troubleshooting: The DFD’s visual explanation of a process simplifies finding possible bottlenecks or other problems in a data flow.
    5. Improved records: Communicating with others is facilitated by visual representations of the data flow in systems or processes.
  • Requirement Analysis in Software Engineering

    Requirement analysis is significant and essential activity after elicitation. We analyze, refine, and scrutinize the gathered requirements to make consistent and unambiguous requirements. This activity reviews all requirements and may provide a graphical view of the entire system. After the completion of the analysis, it is expected that the understandability of the project may improve significantly. Here, we may also use the interaction with the customer to clarify points of confusion and to understand which requirements are more important than others.

    The various steps of requirement analysis are shown in fig:

    Requirements Analysis

    (i) Draw the context diagram: The context diagram is a simple model that defines the boundaries and interfaces of the proposed systems with the external world. It identifies the entities outside the proposed system that interact with the system. The context diagram of student result management system is given below:

    Requirements Analysis

    (ii) Development of a Prototype (optional): One effective way to find out what the customer wants is to construct a prototype, something that looks and preferably acts as part of the system they say they want.

    We can use their feedback to modify the prototype until the customer is satisfied continuously. Hence, the prototype helps the client to visualize the proposed system and increase the understanding of the requirements. When developers and users are not sure about some of the elements, a prototype may help both the parties to take a final decision.

    Some projects are developed for the general market. In such cases, the prototype should be shown to some representative sample of the population of potential purchasers. Even though a person who tries out a prototype may not buy the final system, but their feedback may allow us to make the product more attractive to others.

    The prototype should be built quickly and at a relatively low cost. Hence it will always have limitations and would not be acceptable in the final system. This is an optional activity.

    (iii) Model the requirements: This process usually consists of various graphical representations of the functions, data entities, external entities, and the relationships between them. The graphical view may help to find incorrect, inconsistent, missing, and superfluous requirements. Such models include the Data Flow diagram, Entity-Relationship diagram, Data Dictionaries, State-transition diagrams, etc.

    (iv) Finalise the requirements: After modeling the requirements, we will have a better understanding of the system behavior. The inconsistencies and ambiguities have been identified and corrected. The flow of data amongst various modules has been analyzed. Elicitation and analyze activities have provided better insight into the system. Now we finalize the analyzed requirements, and the next step is to document these requirements in a prescribed format.

  • Software Requirement Specification (SRS) in Software Engineering

    The production of the requirements stage of the software development process is Software Requirements Specifications (SRS) (also called a requirements document). This report lays a foundation for software engineering activities and is constructed when all requirements are elicited and analyzed. SRS is a formal report that acts as a representation of software that enables the customers to review whether it (SRS) is according to their requirements. Also, it comprises user requirements for a system as well as detailed specifications of the system requirements.

    The SRS is a specification for a specific software product, program, or set of applications that perform particular functions in a specific environment. It serves several goals depending on who is writing it. First, the SRS could be written by the system’s client. Second, the SRS could be written by a system developer. The two methods create entirely various situations and establish different purposes for the document altogether. The first case, SRS, is used to define the needs and expectations of the users. The second case, SRS, is written for various purposes and serves as a contract document between the customer and the developer.

    Essential elements of a Software Requirements Document

    A software requirements specification’s primary sections are as follows:

    • Drivers of business: This section outlines the customer’s motivations for wanting the system built, including issues with the existing system and possibilities they hope the new system will offer.
    • Business plan: This section explains the business model that the system will support, along with its organizational structure, business context, key business processes, and process flow diagrams.
    • System, functional, and business needs: The criteria in this section are arranged hierarchically. The specific system needs are listed as child items or subsections, while the functional and business requirements are at the top level.
    • Use cases for systems and businesses: This section’s use case diagram, created using the Unified Modelling Language, shows the main external entities that will communicate with the system and the various services they will offer.
    • Technical Specifications: This section lists the nonfunctional criteria that comprise the technological environment and technical constraints in which the program will work.
    • Characteristics of the system: This section covers the nonfunctional requirements that specify the system’s quality attributes-such as dependability, serviceability, security, scalability, availability, and maintainability.
    • Limitations and Presumptions: This section includes any limitations the client has placed on the system design and any presumptions the requirement’s engineering team has about what will transpire throughout the project.
    • Acceptance standards: This section describes the requirements that must be fulfilled for the client to approve the finished system.

    Why is SRS used?

    An organization’s whole project is built upon an SRS. It lays out the structure that the development team adheres to and gives vital information to all the teams engaged-development, operations, maintenance, and quality assurance. This strategy guarantees team consensus.

    Businesses utilize an SRS to verify that the criteria are met and to assist executives in making choices on product lifecycles, including whether to retire a technology or feature. Writing an SRS may also assist developers in saving money on development expenses and cutting down on the time and effort needed to achieve their objectives.

    Other options than an SRS

    Businesses typically prefer documentation of less detailed requirements when using Agile approaches. These include user stories and acceptance testing in the procedure. The client must be readily available throughout the development process to offer any clarification on the requirements that may be required for this method to be successful. Additionally, it assumes that the developers who collaborate with the client to write user stories will also be the ones developing the system.

    Another alternative software engineering process that prioritizes speed and flexibility above advanced design is rapid application development. This method takes little time to create and usually takes 60 to 90 days to complete a project created using this approach.

    Characteristics of an SRS

    An SRS needs to possess the following qualities:

    Software Requirement Specifications
    1. It should always correctly depict the features and specifications of the product.
    2. There shouldn’t be any misunderstandings about how the requirements should be interpreted.
    3. An SRS is verifiable only when all specified requirements can be confirmed. If there is a way to determine quantitatively whether the finished program satisfies a need, then that requirement is verifiable.
    4. An SRS must systematically and explicitly identify every requirement. The dependent requirements and the particular criteria can be changed in accordance with any modifications without impacting the others.
    5. If each need’s source is evident and it is simple to refer to each requirement in subsequent development, then an SRS is traceable.

    The objectives of an SRS

    The following are a few objectives an SRS should accomplish:

    1. Give the consumer input to make sure the IT department knows what problems the software system should fix and how to fix them.
    2. Simply putting the criteria on paper smight assist in decomposing a challenge into smaller parts.
    3. Accelerate the validation and testing procedures.
    4. Encourage reviews.

    Avoid these mistakes while creating an SRS.

    When creating an SRS, enterprises frequently commit a number of blunders. The following are the most significant errors that a company should avoid:

    1. SRS documents must use clear, unambiguous language, and confusing phrases must be avoided. Making the SRS excessively complex and unusable for team members who might not be technically savvy is another example of this.
    2. Disregarding criteria that are not functional. Many initiatives ignore nonfunctional needs, including usability, speed, and security, in favor of only functional requirements, which are equally crucial to the software product’s success.
    3. Incomplete feedback from stakeholders. There may be significant gaps in the SRS if a company does not involve all stakeholders, particularly end users and business analysts.
    4. Failing to handle updates. Because an SRS is developed dynamically, needs will frequently change. Project delays, rework, and misunderstanding can result from a weak requirements management procedure.
    5. Disregarding accessibility and usability, the SRS must ensure that its product is user-friendly. Its creation should consider accessibility and usability standards as well as how actual users will interact with the system.
  • Personnel Planning

    Personnel Planning deals with staffing. Staffing deals with the appoint personnel for the position that is identified by the organizational structure.

    It involves:

    • Defining requirement for personnel
    • Recruiting (identifying, interviewing, and selecting candidates)
    • Compensating
    • Developing and promoting agent

    For personnel planning and scheduling, it is helpful to have efforts and schedule size for the subsystems and necessary component in the system.

    At planning time, when the system method has not been completed, the planner can only think to know about the large subsystems in the system and possibly the major modules in these subsystems.

    Once the project plan is estimated, and the effort and schedule of various phases and functions are known, staff requirements can be achieved.

    From the cost and overall duration of the projects, the average staff size for the projects can be determined by dividing the total efforts (in person-months) by the whole project duration (in months).

    Typically the staff required for the project is small during requirement and design, the maximum during implementation and testing, and drops again during the last stage of integration and testing.

    Using the COCOMO model, average staff requirement for various phases can be calculated as the effort and schedule for each method are known.

    When the schedule and average staff level for every action are well-known, the overall personnel allocation for the project can be planned.

    This plan will indicate how many people will be required for different activities at different times for the duration of the project.

    The total effort for each month and the total effort for each step can easily be calculated from this plan.

    Team Structure

    Team structure addresses the issue of arrangement of the individual project teams. There are some possible methods in which the different project teams can be organized. There are primarily three formal team structures: chief programmer, Ego-less or democratic, and the mixed team organizations even several other variations to these structures are possible. Problems of various complexities and sizes often need different team structures for the chief solution.

    Ego-Less or Democratic Teams

    Ego-Less teams subsist of a team of fewer programmers. The objective of the group is set by consensus, and input from each member is taken for significant decisions. Group leadership revolves among the group members. Due to its nature, egoless teams are consistently known as democratic teams.

    The structure allows input from all representatives, which can lead to better decisions in various problems. This suggests that this method is well suited for long-term research-type projects that do not have time constraints.

    Personnel Planning

    Chief Programmer Team

    A chief-programmer team, in contrast to the ego-less team, has a hierarchy. It consists of a chief-programmer, who has a backup programmer, a program librarian, and some programmers.

    The chief programmer is essential for all major technical decisions of the project.

    He does most of the designs, and he assigns coding of the different part of the design to the programmers.

    The backup programmer uses the chief programmer makes technical decisions, and takes over the chief programmer if the chief programmer drops sick or leaves.

    The program librarian is vital for maintaining the documentation and other communication-related work.

    This structure considerably reduces interpersonal communication. The communication paths, as shown in fig:

    Personnel Planning

    Controlled Decentralized Team

    (Hierarchical Team Structure)

    A third team structure known as the controlled decentralized team tries to combine the strength of the democratic and chief programmer teams.

    It consists of project leaders who have a class of senior programmers under him, while under every senior programmer is a group of a junior programmer.

    The group of a senior programmer and his junior programmers behave like an ego-less team, but communication among different groups occurs only through the senior programmers of the group.

    The senior programmer also communicates with the project leader.

    Such a team has fewer communication paths than a democratic team but more paths compared to a chief programmer team.

    This structure works best for large projects that are reasonably straightforward. It is not well suited for simple projects or research-type projects.

    Personnel Planning