[TIL] 0725 Interview Prep

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Today I Learnt 

 

0725 :

 

 

 

 

Javascript :

 

How does javascript work ?

It is a single thread but it Support CONCURENCCY work 

memory heap , all the memory allocation ,

call stack all the function goes to stack first.  

and things that takes time (Web API : ajax , set time out, DOM, event listen )  goes to callback Queue 

and when the call stack is EMPTY , then things from queue goes up to stack. (BY EVENT LOOP)

 

 

 

Class & prototype

 

Class Car(brand,model){


    constructor(){
	this.brand = brand
    this.model = model
    }
}

Car.prototype.price="$50000"


const ferrariF430 =new car('ferrari' 'f430')

    
Prototype ?  // it is like DNA 
array.prototype 

array.prototype.customeFunction = function customeFunction(){}

 

 

Two ways to delete the data of the table in SQL

delete and truncate. Delete is DML command truncate is DML command 

https://joshua1988.github.io/web-development/translation/javascript/how-js-works-inside-engine/

자바스크립트의 동작원리: 엔진, 런타임, 호출 스택

DML in SQL ?

DML (Data Manipulation Language) statements are the element in the SQL language that is used for data retrieval and manipulation. Using these statements you can perform operations such as: adding new rows, updating and deleting existing rows, merging tables and so on.

 

DDL in SQL ?

What is DDL in SQL with examples?

Data Definition Language(DDL) is a subset of SQL and a part of DBMS(Database Management System). DDL consist of Commands to commands like CREATE, ALTER, TRUNCATE and DROP. These commands are used to create or modify the tables in SQL.

DML /DML / DCL 

https://m.blog.naver.com/PostView.naver?isHttpsRedirect=true&blogId=potter777777&logNo=220740559802 

DDL, DML, DCL 차이 정리

 

TDD? 

why ?

 

TDD can reduce bugs and act as a code document.

 

when someone changes the code in the future, it can guide the engineer to fix/ modify the existing code.

 

https://medium.com/@sukorenomw/why-tdd-test-driven-development-a1bc983a2cc0

Why TDD (Test Driven Development) ?

 

Infastrcture as code ?

Terraform ?  

 

you can make ec2 instance only with your cli ? 

• Create repeatable version-controlled configurations
• Integrate them as a part of the CI/CD pipeline
• Automate the infrastructure management

 

https://learn.hashicorp.com/tutorials/terraform/infrastructure-as-code

What is Infrastructure as Code with Terraform? | Terraform - HashiCorp Learn

https://www.bmc.com/blogs/terraform/

What Is Terraform? Terraform & Its IaC Role Explained