Friday, January 11, 2019

thumbnail

How to Convert E-R model for Bank Data Base into Relational Model ?


To understand this concept you should have knowledge of the E-R Model and Relational Model. if you don't have an idea please go through volume-2 and volume-3

 E-R model:
                     Let us consider the bank database contains four entities Account, Branch, Customer, and loan. for each entity, there are different attributes. These entities are connected with a relationship set. to know more about relationship set go through volume-4



 E-R model of Bank Data Base



Relational Model: It is the tabular representation of the E-R Model. the relational model represents the Database as the collection of relation.when a relation taught as a table of values each row in the table representing the collection of related data values.

Conversion:

Domain: A domain is defined as the set of all unique values permitted for an attribute. (The value of a particular relation.)

Attribute: An Attribute describes the instances in the row of a database. (The value of the column.)

Tupple:  A single row of a table, which contains a single record for that relation is called a tuple. (The value of the Row.)

Relation: The term relation schema refers to a heading paired with a set of constraints defined in terms of that heading. (The value of the Table.)

The four relations are shown below










Monday, January 7, 2019

thumbnail

What are the Advantages of Data Base Management System over File System?


Welcome To Series Articles of DBMS(volume-6)


Advantages of Data Base Management System:

There are 7 major advantages they are:

1. Controlling the Redundancy.
2. Restricting unauthorized access.
3. Providing the Persistence storage of program data.
4. Providing the storage structure and search technique for efficient query processing.
5. Backup and Recovering.
6. Providing the multiplex interface.
7. Entering the integrity.

1. Controlling the Redundancy.
Redundancy is storing the same data multiple times leads to several problems.it is otherwise known as data duplicate for a particular database the value must be unique the job of database user is that to control the redundancy by using normalization technique.

2. Restricting unauthorized access.
When multiple users share a large database it is likely that most users will not be authorized to access all the information in the database, for example, The finance data is often considered as a confidential and only otherized person are allowed to access such data. The DBMS should provide security and authorized subsystem which the DBA user to create an account and to specify the account restriction. The DBMS should enforce these restrictions automatically.

3. Providing the Persistence storage of program data.
The database can be used to provide persistent storage of program object and data structure this is one of the main reason for the object-oriented database programming language typically have a complex data structure such as record types in c,c++ and java. the programmer having full authority to access the particular code from the programming database.

4. Providing the storage structure and search technique for efficient query processing.
The database system must provide the capability for efficiently executing queries and objects because the database is typically stored on disk. DBMS must provide specialize data structure and speed up the search for the desired record. the query process and optimized module of DBMS is responsible for choosing an efficient query execution plan for each query based on the existing storage structure.

5. Backup and Recovering.
A DBMS must provide the facilities for recovering from hardware and software failures the backup and recovery system of DBMS is responsible for recovery. for example, if the computer system fails in the middle of a transaction the recovery is responsible for make sure that the database is stored to the state it was in before the transaction started executing.

6. Providing the multiplex interface.
Many types of users with varying levels of tech knowledge use DBMS. It could provide a variety of user interface. these include the query language for the casual user, programming language interface for the application user, forms and command code for parametric user and memory return and natural interface for the standalone user.

7. Entering the integrity constraints.
Most of the database application has certain integrity constant that must hold for the data. DBMS should provide the capability for defining and enforcing these constraints.there are two constraints one is the primary key constraint or unique key and the other is referential integrity or integrity constraints or foreign key. 



I hope this article is useful to you, plz follow the next volume for more information.
                        
please post your doubts in the comment box.  


You can write to me at codingallrounders@gmail.com



thumbnail

Software Engineering Interview Questions and Answers.


Q. What is computer software?
A. Computer software is a complete package, which includes a software program, its documentation, and user guide on how to use the software.

Q. Can you differentiate computer software and a computer program?
A. A computer program is a piece of programming code which performs a well-defined task whereas software includes programming code, its documentation and user guide.

Q. What is software engineering?
A. Software engineering is an engineering branch associated with software system development.

Q. When you know to the programme, what is the need to learn software engineering concepts?
A. A person who knows how to build a wall may not be good at building an entire house. Likewise, a person who can write programs may not have knowledge of other concepts of Software Engineering. The software engineering concepts guide programmers on how to assess the requirements of the end user, design the algorithms before actual coding starts, create programs by coding, testing the code and its documentation.

Q. What is a software process or Software Development Life Cycle (SDLC)?
A. Software Development Life Cycle or software process is the systematic development of software by following every stage in the development process namely, Requirement Gathering, System Analysis, Design, Coding, Testing, Maintenance, and Documentation in that order.

Q. What are the SDLC models available?
A. There are several SDLC models available such as the Waterfall Model, Iterative Model, Spiral model, V-model and Big-bang Model etc.

Q. What are various phases of SDLC?
A. The generic phases of SDLC are Requirement Gathering, System Analysis, and Design, Coding, Testing and implementation. The phases depend upon the model we choose to develop software.

Q. Which SDLC model is the best?
A. SDLC Models are adopted as per requirements of the development process. It may very software-to-software to ensuring which model is suitable.
We can select the best SDLC model if the following answers are satisfied -
  • Is SDLC suitable for selected technology to implement the software?
  • Is SDLC appropriate for client’s requirements and priorities ?
  • Is the SDLC model suitable for the size and complexity of the software?
  • Is the SDLC model suitable for a type of projects and engineering we do?
  • Is the SDLC appropriate for the geographically co-located or dispersed developers?

Q. What is software project management?
A. Software project management is the process of managing all activities like time, cost and quality management involved in software development.

Q. Who is a software project manager?
A. A software project manager is a person who undertakes the responsibility of carrying out the software project.

Q. What does the software project manager do?
A. The software project manager is engaged in software management activities. He is responsible for project planning, monitoring the progress, communication among stakeholders, managing risks and resources, smooth execution of development and delivering the project within time, cost and quality constraints.

Q. What is software scope?
A. Software scope is a well-defined boundary, which encompasses all the activities that are done to develop and deliver the software product.
The software scope clearly defines all functionalities and artifacts to be delivered as a part of the software. The scope identifies what the product will do and what it will not do, what the end product will contain and what it will not contain.

Q. What is project estimation?
A. It is a process to estimate various aspects of the software product in order to calculate the cost of development in terms of efforts, time and resources. This estimation can be derived from past experience, by consulting experts or by using pre-defined formulas.

Q. How can we derive the size of the software product?
A. Size of the software product can be calculated using either of two methods -
  • Counting the lines of delivered code
  • Counting delivered function points

Q. What are function points?
A. Function points are the various features provided by the software product. It is considered as a unit of measurement for software size.

Q. What are software project estimation techniques available?
A. There are many estimation techniques available. The most widely used are -
  • Decomposition technique (Counting Lines of Code and Function Points)
  • Empirical technique (Putnam and COCOMO).

Q. What is the baseline?
A. The baseline is a measurement that defines the completeness of a phase. After all, activities associated with a particular phase are accomplished, the phase is complete and acts as a baseline for the next phase.

Q. What is Software configuration management?
A. Software Configuration management is a process of tracking and controlling the changes in software in terms of the requirements, design, functions, and development of the product.

Q. What is change control?
A. Change control is the 
function of configuration management, which ensures that all changes made to the software system are consistent and made as per organizational rules and regulations.

Q. How can you measure project execution?
A. We can measure project execution by means of Activity Monitoring, Status Reports, and Milestone Checklists.

Q. Mention some project management tools.
A. There are various project management tools used as per the requirements of software project and organization policies. They include Gantt Chart, PERT Chart, Resource Histogram, Critical Path Analysis, Status Reports, Milestone Checklists etc.

Q. What are software requirements?
A. Software requirements are a functional description of the proposed software system. Requirements are assumed to be the description of the target system, its functionalities, and features. Requirements convey the expectations of users from the system.

Q. What is feasibility study?
A. It is a measure to assess how practical and beneficial the software project development will be for an organization. The software analyzer conducts a thorough study to understand the economic, technical and operational feasibility of the project.
· Economic - Resource transportation the cost for training, cost of additional utilities and tools and overall estimation of costs and benefits of the project.
· Technical - Is it possible to develop this system? Assessing the suitability of machine(s) and operating system(s) on which software will execute, existing developers’ knowledge and skills, training, utilities or tools for the project.
· Operational - Can the organization adjust smoothly to the changes done as per the demand of project? Is the problem worth solving?

Q. How can you gather requirements?
A. Requirements can be gathered from users via interviews, surveys, task analysis, brainstorming, domain analysis, prototyping, studying existing usable version of the software, and by observation.

Q. What is SRS?
A. SRS or Software Requirement Specification is a document produced at the time of requirement gathering process. It can be also seen as a process of refining requirements and documenting them.

Q. What are functional requirements?
A. Functional requirements are functional features and specifications expected by users from the proposed software product.

Q. What are non-functional requirements?
A. Non-functional requirements are implicit and are related to security, performance, look and feel of user interface, interoperability, cost etc.

Q. What is the software measure?
A. Software Measures can be understood as a process of quantifying and symbolizing various attributes and aspects of software.

Q. What is the software metric?
A. Software Metrics provide measures for various aspects of software process and software product. They are divided into –
  • Requirement metrics: Length requirements, completeness
  • Product metrics: Lines of Code, Object-oriented metrics, design, and test metrics
  • Process metrics: Evaluate and track budget, schedule, human resource.

Q. What is modularization?
A. Modularization is a technique to divide a software system into multiple discrete modules, which are expected to carry out the task(s) independently.

Q. What is concurrency and how it is achieved in software?
A. Concurrency is the tendency of events or actions to happen simultaneously. In software, when two or more processes execute simultaneously, they are called concurrent processes.
Example
While you initiate print command and printing starts, you can open a new application.
Concurrency is implemented by splitting the software into multiple independent units of execution namely processes and threads and executing them in parallel.

Q. What is cohesion?
A. Cohesion is a measure that defines the degree of intra-dependability among the elements of the module.

Q. What is coupling?
A. Coupling is a measure that defines the level of inter-dependability among modules of a program.

Q. Mentions some software analysis & design tools?
A. These can be DFD (Data Flow Diagrams), Structured Charts, Structured English, Data Dictionary, HIPO (Hierarchical Input Process Output) diagrams, ER (Entity Relationship) Diagrams, and Decision Tables.

Q. What is level-0 DFD?
A. Highest abstraction level DFD is known as Level 0 DFD also called a context level DFD, which depicts the entire information system as one diagram concealing all the underlying details.

Q. What is the difference between structured English and Pseudo Code?
A. Structured English is native English language used to write the structure of a program module by using programming language keywords, whereas, Pseudo Code is more close to the programming language and uses native English language words or sentences to write parts of the code.

Q. What is data dictionary?
A. The data dictionary is referred to as meta-data. Meaning, it is a repository of data about data. The data dictionary is used to organize the names and their references used in the system such as objects and files along with their naming conventions.

Q. What is a structured design?
A. Structured design is a conceptualization of problem into several well-organized elements of the solution. It is the concern with the solution design and based on ‘divide and conquer’ strategy.

Q. What is the difference between function-oriented and object-oriented design?
A. The function-oriented design is comprised of many smaller sub-systems known as functions. Each function is capable of performing a significant task in the system. The object-oriented design works around the real world objects (entities), their classes (categories) and methods operating on objects (functions).

Q. Briefly define top-down and bottom-up design model.
A. Top-down model starts with a generalized view of system and decomposes it to more specific ones, whereas bottom-up model starts with most specific and basic components first and keeps composing the components to get higher level of abstraction.

Q. What is the basis of Halstead’s complexity measure?
A. Halstead’s complexity measure depends up on the actual implementation of the program and it considers tokens used in the program as a basis of measure.

Q. Mention the formula to calculate Cyclomatic complexity of a program?
A. Cyclomatic complexity uses graph theory’s formula: V(G) = e – n + 2

Q. What is functional programming?
A. Functional programming is style of programming language, which uses the concepts of mathematical function. It provides means of computation as mathematical functions, which produces results irrespective of program state.

Q. Differentiate validation and verification?
A. Validation checks if the product is made as per user requirements whereas verification checks if proper steps are followed to develop the product.
Validation confirms the right product and verification confirms if the product is built in a right way.

Q. What is black-box and white-box testing?
A. Black-box testing checks if the desired outputs are produced when valid input values are given. It does not verify the actual implementation of the program.
White-box testing not only checks for desired and valid output when valid input is provided but also it checks if the code is implemented correctly.
Criteria
Black Box Testing
White Box Testing
Knowledge of software program, design and structure essential
No
Yes
Knowledge of Software Implementation essential
No
Yes
Who conducts this test on software
Software Testing Employee
Software Developer
baseline reference for tester
Requirements specifications
Design and structure details

Q. Quality assurance vs. Quality Control?
A. Quality Assurance monitors to check if proper process is followed while software developing the software.
Quality Control deals with maintaining the quality of software product.

Q. What are various types of software maintenance?
A. Maintenance types are: corrective, adaptive, perfective and preventive.
  • Corrective
Removing errors spotted by users
  • Adaptive
tackling the changes in the hardware and software environment where the software works
  • Perfective maintenance
implementing changes in existing or new requirements of user
  • Preventive maintenance
taking appropriate measures to avoid future problems

Q. What is software re-engineering?
A. Software re-engineering is process to upgrade the technology on which the software is built without changing the functionality of the software. This is done in order to keep the software tuned with the latest technology.

Q. What are CASE tools?
A. CASE stands for Computer Aided Software Engineering. CASE tools are a set of automated software application programs, which are used to support, accelerate and smoothen the SDLC activities.



I hope this article is useful to you.
                        
please post your doubts in the comment box.  

You can write to me at codingallrounders@gmail.com


thumbnail

What are Top 50 Software Engineering Interview Questions and Answers ?


1. What is Software Testing?
A set of activities conducted with the intent of finding errors in software.

2. What is Acceptance Testing?

Testing conducted to enable a user/customer to determine whether to accept a software product. Normally performed to validate the software meets a set of agreed acceptance criteria.


3. What is Accessibility Testing?

Verifying a product is accessible to the people having disabilities (deaf, blind, mentally disabled etc.).


4.  What is Ad Hoc Testing?

A testing phase where the tester tries to 'break' the system by randomly trying the system's functionality.


5. What is the Application Programming Interface (API)?
A formalized set of software calls and routines that can be referenced by an application program in order to access supporting system or network services.


6. What is Backus-Naur Form?
A metalanguage used to formally describe the syntax of a language.

7.  What is Beta Testing?
Testing of a release of a software product conducted by customers.

8. What is Application Binary Interface (ABI)?
A specification defining requirements for portability of applications in binary forms across different system platforms and environments.


9. What is Binary Portability Testing?
Testing an executable application for portability across system platforms and environments, usually for confirmation to an ABI specification.


10. What is Black Box Testing?
Testing based on an analysis of the specification of a piece of software without reference to its internal workings. The goal is to test how well the component conforms to the published requirements for the component.


11.  What is Bottom Up Testing?
An approach to integration testing where the lowest level components are tested first then used to facilitate the testing of higher level components. The process is repeated until the component at the top of the hierarchy is tested.

12. What is Boundary Testing?

Test which focuses on the boundary or limit conditions of the software being tested. (Some of these tests are stress tests).


13. What is the difference between verification and validation?

Verification is a review without actually executing the process while validation is checking the product with actual execution. For instance, code review and syntax check is verification while actually running the product and checking the results is validation.


14. What is Bug?

A fault in a program which causes the program to perform in an unintended or unanticipated manner.

15. What is Defect?

If software misses some feature or function from what is there in requirement it is called as the defect.


16.  What is Branch Testing?

Testing in which all branches in the program source code are tested at least once.


17. What is Breadth Testing?

A test suite that exercises the full functionality of a product but does not test features in detail.


18. What's the Alpha Testing?

The Alpha Testing is conducted at the developer sites and in a controlled environment by the end user of the software


19. What's the Beta Testing?

Testing the application after the installation at the client place.


20. What is Component Testing?
Testing of individual software components (Unit Testing).


21. What is End-to-End testing?
Testing a complete application environment in a situation that mimics real-world use, such as interacting with a database, using network communications, or interacting with other hardware, applications, or systems if appropriate.


22.  What is CAST?
Computer Aided Software Testing.


23.  What is CMM?
The Capability Maturity Model for Software (CMM or SW-CMM) is a model for judging the maturity of the software processes of an organization and for identifying the key practices that are required to increase the maturity of these processes.


24. What is Cause Effect Graph?
A graphical representation of inputs and the associated outputs effects which can be used to design test cases.


25. What is Coding?
The generation of source code.


26. What is Compatibility Testing?

Testing whether the software is compatible with other elements of a system with which it should operate, e.g. browsers, Operating Systems, or hardware.


27. What is Cyclomatic Complexity?

A measure of the logical complexity of an algorithm, used in white-box testing.


28. What is Debugging?

The process of finding and removing the causes of software failures.


29. What is Dependency Testing?

Examines an application's requirements for pre-existing software, initial states, and configuration in order to maintain proper functionality.
 30. What are the different Ways of doing Black Box testing?

There are five methodologies most frequently used:
A)Top-down according to budget
B)WBS (Work Breakdown Structure)
C)Guess and gut feeling
D)Early project data
E)TPA (Test Point Analysis)


31. What
s the Database testing?

In database testing, we can check the integrity of database field values.


32. How many types of testing?

There are two types of testing-
Functional- Black Box Testing
Structural- white Box Testing


33. What does the mclabe cyclomatic complexity of a program determine?

Cyclomatic complexity is likely the most widely used complexity metric in software engineering. It describes the complexity of a procedure by measuring the linearly independent paths through its source code.


34. What is the difference between interoperability and compatibility testing with some examples?

Interoperability:-To check if the software can co-exist with other supporting software in the system.

Compatibility:-To check if the software runs on different types of operating systems according to customer requirements.


35. Which testing method is used to check the software in an abnormal condition?
1) Stress testing
2) Security testing
3) Recovery testing
4) Beta testing



36. What
is the Test Case?

A set of test inputs, execution, and expected result developed for a particular objective.


37. What
is the Traceability Matrix?

A document showing the relationship between Test Requirements and Test Cases.


38. How many types of approaches are used in Integration Testing?

There are two types of approaches used-
Bottom-Up
Top-Down


39. What is Emulator?
A device, computer program, or system that accepts the same inputs and produces the same outputs as a given system.

40. What is Functional Decomposition?
A technique used during planning, analysis, and design; creates a functional hierarchy for the software.

41. What is Glass Box Testing?

A synonym for White Box Testing.

42. What is Gorilla Testing?
Testing one module, functionality heavily.


43. What is Gray Box Testing?
A combination of Black Box and White Box testing methodologies testing a piece of software against its specification but using some knowledge of its internal workings.


44. What is Integration Testing?

Testing of combined parts of an application to determine if they function together correctly. Usually performed after unit and functional testing. This type of testing is especially relevant to client/server and distributed systems.

45. What is Metric?
A standard of measurement. Software metrics are the statistics describing the structure or content of a program. A metric should be a real objective measurement of something such as the number of bugs per lines of code.

46. What is Quality Assurance?

All those planned or systematic actions necessary to provide adequate confidence that a product or service is of the type and quality needed and expected by the customer.


47. What is Quality Control?

The operational techniques and the activities used to fulfill and verify requirements of quality.

48. What is Race Condition?

A cause of concurrency problems. Multiple accesses to a shared resource, at least one of which is a write, with no mechanism used by either to moderate simultaneous access.

49. What is Scalability Testing?
Performance testing focused on ensuring the application under test gracefully handles increases in workload.

50. What is the Software Requirements Specification?

A deliverable that describes all data, functional and behavioral requirements, all constraints, and all validation requirements for software.




I hope this article is useful to you.
                        
please post your doubts in the comment box.  

You can write to me at codingallrounders@gmail.com



Powered by Blogger.