摘要： 1. One to many relations: one value in column in table one related to several values in the column in table two. In this case, we need to be very clea 阅读全文

摘要： Data Schema is the table which contains all the data types of another table. 1. Add column in schema table for the main table by using ALTER TABLE... 阅读全文

摘要： 1.Working with dates in SQL: in SQL query, we can select date by using where. < means before that date, and > means after that date: SELECT * FROM fac 阅读全文

摘要： 1. GROUP BY function The group by function will categroy the table according to different requirement: Select Employed, Major_category, SUM(Employed) 阅读全文

摘要： 1. In SQL, we can use count in the query to get the number of a column in the table. query = "select count(birth_rate) from facts;" 2. Also, we can us 阅读全文

摘要： Querying SQLite from Python 1. We use connect() in the library sqlite3 to connect the database we would like to query. Once it is connected, the targe 阅读全文

摘要： SQL And Database: 1.SQL query is to request the data from the database. 2.We use SELECT command to pick the specific column from the database. SELECT 阅读全文

摘要： Web Scriping: 1. We can also use requests.get to get the HTML file form a webpage. 2. If we would like to extract the content from the webpage, we can 阅读全文

摘要： 1. While we would like to get some data from the server with authorization, we should apply token from the website frist. Then we pass token in the re 阅读全文

摘要： 1. The API is the link to request data from the host. 2. A endpoint is a route to retrive different data from the API. 3. Status codes indicate inform 阅读全文