Database Study Note: What's The Difference Between SQL and NoSQL?

What is Database?

According to the course, the database is not only a collection of information data, but it also an interface to interact with data such as add new data, remove data, or edit data.

Two Broad Categories of Database:

SQL (sequel)

SQL is also called relational database. Sequel database are tabular database which data is stored in a table.

From Google Image

NoSQL(non-sequel)

For NoSQL, they are no tables, and it is basically JavaScript objects with a bunch of key value pairs.

What's the difference between SQL and NoSQL?

SQL has been around the longest. When we mention database, most people include myself first think of table. Everything is tabular, and if we want to relate data, we have to build other tables to relate that data.

However, NoSQL is non-relational database, so we don't have to define any tables and patterns. This is a much more flexible structure.

The course also mentioned that flexible structure is better then flat structure(like table). It just depending on how we use database.

Comments

Intermediate Express.js: How To Add Styles & Partials in EJS File?

So far, we only have simple HTML tags and ejs tags in each ejs file. Every template page has no style at all. And the basic HTML header and footer are also missing. Today, I learned how to add styles and partials in ejs file. Link Style Step One: Touch a Separate CSS file I create a new directory "Style" under the "EJSDemo" directory, then I add a new CSS file "app.css" inside "Style" folder. Step Two: Add app.use(express.static()) in the app.js I add app.use(express.static("style")) in the "app.js". This will tell Express.js to serve the content of "Style" directory. Step Three: Write styles in CSS file I simple give body an orange background color and set text color to be grey. Step Four: Link to CSS file in the EJS file I just add <link> tag to link the "app.css" file on the top of the h1 tag in each ejs template. As the result, when I run the app and...

Seven Most Common jQuery Methods Last Part: ADD/REMOVE/TOGGLE CLASS()

Add, remove and toggleClass is also a very common way to manipulate style. .addClass() and .removeClass() I add two class selector in the style tag. Class one is to change text color to be green, and class two is change both text and background color. Now I refresh the page and change h1 text to green by using addClass() method: $("h1").addClass("one") . If you want to remove the style, you can change it to removeClass("one"). I do the same thing to the list. I change the list color and add a background color by adding the class two style value: $("li").addClass("two") . .toggleClass() According to jQuery, toggerClass method can add or remove one or more classes from each element in the set of matched elements, depending on either the class's presence or the value of the state argument. I only want to change the first list item color and background by writing: $("li").first().toggleClas...

My Story: A Mommy Start To Learn Code From Zero

From Google Image I am not a programmer, and I thought I would never become one. Everytime I see someone is coding, I think he or she must be very talent. For me, coding is a very difficult subject to learn. Not only the language has so many rules, but also the logical reasoning behind the language is complex. In my graduated school, I knew many friends who didn't have any coding background, but they are doing programmer or developer jobs now. Some of them went to school to study coding, and some of them learned to code by themselves. Their stories are so impressive. I wasn't ready to learn code until I finished my first Chinese book "留学，我的青春呀!" recently. I always want to be a writer and write my own book. I started writing blog three years ago, and I updated my post two to three times every week. As I enjoyed writing , I started to get some followers, likes, and good comments on my blog. Then, I decided to plan my first book. My First...

Learn Bootcamp From Zero

Search This Blog