Скачать или смотреть How to Efficiently Load Data into SQLite: The COPY Alternative for PostgreSQL Users

Discover how to easily import tab-delimited text files into your local SQLite database using Python. Follow our simple guide to streamline your data loading process!
---
This video is based on the question https://stackoverflow.com/q/65154361/ asked by the user 'Henru' ( https://stackoverflow.com/u/12153984/ ) and on the answer https://stackoverflow.com/a/65154413/ provided by the user 'Tim Biegeleisen' ( https://stackoverflow.com/u/1863229/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Is there a SQLite equivalent to COPY from PostgreSQL?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Loading Data into SQLite: Finding an Alternative to PostgreSQL's COPY

When transitioning from PostgreSQL to SQLite, many developers wonder how to achieve similar functionality, especially when it comes to loading data from files into a database. If you are accustomed to PostgreSQL's COPY command, you might find yourself searching for an equivalent method in SQLite. In this guide, we’ll explore an effective way to load local tab-delimited raw data files into SQLite using Python.

The Challenge

Suppose you have local text files named publisher.txt and field.txt. You've defined corresponding tables in your SQLite database, and now you want to seamlessly integrate the data from these files into your existing tables. Unlike PostgreSQL, which offers the handy COPY command for this task, SQLite lacks a similar feature called readfile, leading to some confusion among users transitioning from one database to another.

For instance, attempts to use the INSERT command combined with readfile might throw an error like this:

[[See Video to Reveal this Text or Code Snippet]]

This error indicates that readfile is not a recognized function in SQLite, creating a significant hurdle for users accustomed to PostgreSQL's seamless operations.

The Solution

Fortunately, loading data into SQLite isn't as complicated as it might seem! By reading the contents of your text files into a Python string, you can then insert this data into your SQLite database. Here’s how you can do it step-by-step.

Step 1: Set Up Your Python Environment

Ensure you have the sqlite3 library available, as this will let you interact with your SQLite database. If you’re using Jupyter Notebooks, that’s a great place to start.

Step 2: Prepare Your SQL Command

To insert data, you’ll need an SQL command that placeholders the data you want to insert. Below is the template:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Read the File and Insert Data

Here’s a simple Python script to read the contents of your text file and insert it into the SQLite database:

[[See Video to Reveal this Text or Code Snippet]]

Breakdown of the Code

Connecting to Database: First, we establish a connection to our SQLite database using sqlite3.connect().

Reading the File: The contents of publisher.txt are read and combined into a single string using a join operation.

Executing the Query: The cur.execute() method runs the SQL command, inserting the file name and its contents.

Committing Changes: The conn.commit() saves the changes to the database.

Closing Connection: Finally, always close the connection to maintain database integrity and free resources.

Conclusion

While SQLite doesn’t have a direct equivalent to PostgreSQL’s COPY command, using a method like the one demonstrated above allows you to effectively load data from text files into your SQLite database. Following these clear steps not only simplifies the process but also ensures that you can leverage your existing data easily and effectively. With practice, this workflow will soon become a seamless part of your data management process in SQLite.

If you have any other questions or tricks related to SQLite and data imports, feel free to share them in the comments below!