![]() Python’s great support for sqlite will make you love it in no time. It’s a great database when you’d like relational database query functionality without the overhead of Postgres. Sqlite databases are great for local experimentation and are used extensively on mobile phones. Python’s build in sqlite library coupled with Pandas DataFrames makes it easy to load CSV data into sqlite databases. import ' command to import CSV (comma separated value) data into an SQLite table. pd.read_sql('''SELECT * FROM users u LEFT JOIN orders o ON u.user_id = o.user_id''', conn) Next steps You can also read the SQL query directly into a Pandas DataFrame. You can then simply copy the entire sqlite file onto the device when your application is first run. Here’s the array that’s returned: [(1, 'pokerkid', 1, 1, 'speaker'), If you want to package static data with your application, I recommend preparing the database at development time (using any UI or csv-import command you like) and shipping the sqlite file inside the assets folder. Join the users and orders tables on the user_id value and print the results: c.execute('''SELECT * FROM users u LEFT JOIN orders o ON u.user_id = o.user_id''') Orders.to_sql('orders', conn, if_exists='append', index = False) # write to sqlite table Fetch results of database join Orders = pd.read_csv('orders.csv') # load to DataFrame It is treating it as a string and that column value is stored as 'N' instead of NULL. c.execute('''CREATE TABLE orders (order_id int, user_id int, item_name text)''') Run the SQLite3 program by typing a command use the following example as a. In this CSV file, the NULL values are written as N Now I want to import this data into sqlite database, but I am unable to tell sqlite that N are null values. Suppose you have the following orders.csv file: order_id,user_id,item_nameĬreate a table and then load the orders data into the database. Cursors can be thought of as iterators in the database world. The fetchall() method returns an array of tuples.Ĭ.execute() returns a sqlite3.Cursor object. Fetch values from sqlite tableįetch all the rows from the users table: c.execute('''SELECT * FROM users''').fetchall() # The to_sql method makes it easy to write DataFrames to databases. Users.to_sql('users', conn, if_exists='append', index = False) Pandas makes it easy to load this CSV data into a sqlite table: import pandas as pd Suppose you have the following users.csv file: user_id,username c.execute('''CREATE TABLE users (user_id int, username text)''') Load CSV file into sqlite table import sqlite3Įxecute a query that’ll create a users table with user_id and username columns. You can create the file with touch my_data.db or with this equivalent Python code: from pathlib import PathĪ zero byte text file is a great starting point for a lightweight database! Creating sqlite tableĬreate a database connection and cursor to execute queries. Sqlite is a lightweight database that can be started as an empty text file. ![]() Python is perfect language for this task because it has great libraries for sqlite and CSV DataFrames. ![]() This blog post demonstrates how to build a sqlite database from CSV files.
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