This is a personal note to prepare for Software Engineer position.


Algorithm Analysis:



Here are instruction steps to install Oracle instant Client on Ubuntu

cd /opt/
sudo mkdir /opt/oracle

2. Download and unzip Oracle Instant Client at opt/oracle .

sudo wget unzip instantclient_21_4

3. Install linux asynchronous I/O library called libaio .

sudo apt update

The fundamental concepts necessary for designing, using and implementing database systems. It includes the fundamentals of database modeling and design, relational theory and the Structured Query Language (SQL).

Status: still writing…(will end on September, no longer working on it)

Week 1

If you are using Oracle SQL offset :number fetch next :number rows only , you must know that offset does not represent page number.

If you are trying to use it as page number, here is formula:

offset : ( rowLimitPerPage * pageNumber ) - rowLimitPerPage 

In tech term, the OFFSET clause specifies the number of rows to skip before starting to return rows from the query.

In simple term, the OFFSET clause is the starting point of row number, it is a variable to specific from which row you are going to query up to which row FETCH NEXT .

How OFFSET and FETCH NEXT works.


In your NodeJS, you declare to respond with a cookie in its header:

response.cookie("accessToken", accessToken, {
expires: new Date( + 60_000), // 60 seconds

But the client does not save cookies from its reponse header because you must specify withCredential in your axio configuration:

const instance = axios.create({
baseURL: '',
withCredential: true

Check if your rows are already commited in your database.

Use the COMMIT statement to end your current transaction and make permanent all changes performed in the transaction. A transaction is a sequence of SQL statements that Oracle Database treats as a single unit. This statement also erases all savepoints…

Cing Sian Dal

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