Infosys Review

What is a class?

- A class is a function that acts as a blueprint to create objects -Class declarations can not be hoisted

What is agile methodology?

- Iterative and incremental development - Requirements and solutions evolve via cross-functional self-organizing teams - Adaptive planning rather than predictive planning - Flexible response to changes - Software delivery is the measure of progress

What is a constructor?

- is a special method for creating and initalizing an object that was created with a class. -would use super keyword to access and call functions from parent and must be called before first this

What are the four parts of oop?

-Abstraction -Polymorphism -Encapsulation -Inheritance

What is asynchronous programming?

-Help deal with javascript being single threaded -Essentially allows you to do other things while you wait -So if you run a fetch to an api to get the data and there are other parts of your code that could run then it will run those parts regardless of if the fetch is complete

Inheritance

-Inheritance lets one object acquire the properties and methods of another object. In JavaScript this is done by Prototypal Inheritance. Reusability is the main benefit here. We know sometimes that multiple places need to do the same thing, and they need to do everything the same except for one small part. This is a problem inheritance can solve. -Whenever we use inheritance, we try to make it so that the parent and the child have high cohesion. Cohesion is how related your code is.

Polymorphism

-Means many forms -Allows you to manipulate data and change it with proper inheritance -If you need to change a method in a child to make a small change you can override it to fit the situation

What is a RESTful API?

-Representational State Transfer", and was introduced and defined by Roy Fielding in his 2000 doctoral shape. It is a set of rules that, if developers want their API to be RESTful, they follow when creating their API. -Client and server are separate: this is what we described in the above chapters! Stateless: no client context is stored server-side in between requets, all information needed for each request has to be given each time by the client. For example, if I'm making multiple API calls about a user, I need to specify which user each time, the server doesn't store anything between requests. Again, we just talked about this in the previous chapter. Cacheable: Responses from the server have to let the client know if they are cacheable. Layered system: Can have an intermediary server to improve load balances and speed when more users are using the system. Code on demand: This is optional. The ability to pass code from server to client, to allow the client to run it. Uniform interface: This is fundamental to REST

What is the scrum process?

-Scrum is a subset of Agile 1. Work is done in small teams (3 to 9 typically) where the team has all the necessary skills to develop products (Cross Functional teams). 2. Work is planned and executed in short cyclical time frames typically 1 to 4 weeks - Cycles (Sprint) (also called Iteration in general Agile terminology). 3. Only one person decides the work priorities - not a committee or a group (Product Owner via Product Backlog). 4. The team works in an un-interrupted manner during the cycle (Sprint Planning / Sprint Goal). 5. The team gets market information and customer needs from either the customer directly or from someone representing the customer (Product Owner). 6. Only the team can decide how much work it can do in a given Cycle (Sprint Planning / Sprint Goal / Sprint Backlog). 7. Only the team decides HOW it can get the work done (self organisation). 8. The team gets Clarity on WHY it is doing WHAT it is doing before starting the work (Sprint Goal). 9. The team regularly / immediately gets feedback from customers / stakeholders on how well the developed product is meeting the customer needs (Sprint Review). 10. Team continuously improves by reflecting on its practices and behaviour and learning from mistakes regularly (mostly Retrospective / Review but all Scrum events provide feedback). 11. The whole team collaborates while working on a customer need (User Story - Cross Functional). 12. Blockers are immediately raised and discussed on a daily basis if not more frequently (Daily Scrum).

What is abstraction? And what a code example/real life example?

-To abstract something away means to hide away the implementation details inside something - with something like a function -function hitAPI(type){ if (type instanceof InitialLoad) { // Implementation example } else if (type instanceof NavBar) { // Implementation example } else { // Implementation example } } -lots of redundancy -When it could be -hitApi('www.kealanparr.com', HTTPMethod.Get) -All someone has to know is the api link they want to use and the type of HTTP method to make the request

what is a method? and how to create a new instance?

//Method 1 start() { console.log(`This ${this.make} ${this.model}'s engine started.`) } //Method 2 stop() { console.log(`This ${this.make} ${this.model}'s engine stopped.`) } } /** *? NEW INSTANCE - using the keyword 'new' we can create a new object/instance of the AutoMobile class */ // new object/instance of the class let hondaCivic = new AutoMobile('Honda', 'Civic'); hondaCivic.start(); hondaCivic.stop();

What are SQL joins? How to use them to fetch data from multiple tables?

Joins are used to get results from multiple tables using primary and foreign keys of the related tables -Try to explain example then peak page

Can a primary key be empty?

No then there is no way to identify the row or their could be

What is the difference between unique key, foreign key and primary key?

Primary key - identifies each row in a table. For example, in the student table, student_id can be the primary key used to access the details of student. student_id will always be different for different students. Can't be null. Unique key - set of one or more fields that collectively identify a database record. This should not include the primary key. Unique key can have one null value. For example, student_name and batch_number can be collectively used to identify top students in last 3 years. Foreign key - a column that references the column of another table to establish the relationship between two tables. Most of the times, the primary key in one table is the foreign key in another. For example, the book table can have student_id as a foreign key that will determine the details of the books a student has taken.

What is RDBMS?

Relational Database Management System (RDBMS) is a set of programs that helps a developer to interact with the database for creating, updating or deleting data. This is done through queries (SQL). For example, each data element can be a row in the table.

What is encapsulation?

Removing access to parts of your code and making things private is exactly what Encapsulation is all about (often times, people refer to it as data hiding). Why should we prefer privacy? Why not just have everything global? Lots of unrelated bits of code will become dependent/coupled to one another via the global variable. You will likely override the variables if the name get's reused, which can lead to bugs or unpredictable behaviour. You will likely end up with Spaghetti Code - code that's hard to reason through and follow what is reading and writing to your variables and changing state.

What is a database schema?

Schema is a logical representation or structure of the entire database. It defines how the data is organized, associated and stored in the database.

What are the 6 parts of SDLC? And what is it?

Software Development Life Cycle (SDLC) is an end to end process that defines the flow of the development of a project from requirements stage to the maintenance and support stage. The stages in SDLC are requirements analysis, planning, definition, design, development, testing, deployment, and support (maintenance). -Planning -Defining -Designing -Building -Testing -Deployment

What does SDLC stand for?

Systems Development Life Cycle

What are SQL triggers?

Triggers are stored procedures that are invoked when some event like insert, update or delete happens in the database on a particular table.

What is waterfall method

Waterfall approach was first SDLC Model to be used widely in Software Engineering to ensure success of the project. In "The Waterfall" approach, the whole process of software development is divided into separate phases. In this Waterfall model, typically, the outcome of one phase acts as the input for the next phase sequentially.