Python Database Retrieval: Query Data Guide

1 year ago
Ava Mitchell
2 minutes

In Python, you have the option to utilize various libraries to connect to and retrieve data from databases, with the most common ones being sqlite3 and pymysql.

Here is an example of connecting and retrieving data from an SQLite database using the sqlite3 library.

  1. sqlite3 a queried database system
import sqlite3
  1. Connect to the database:
conn = sqlite3.connect('database.db')

Here, assuming your database file is named database.db, if the file does not exist, the sqlite3 library will automatically create a new database file.

  1. Create a cursor object and execute a SQL query.
cursor = conn.cursor()
cursor.execute('SELECT * FROM table_name')

The table_name here refers to the name of the table you want to query, and you can modify the query statement as needed.

  1. Get search results:
result = cursor.fetchall()

This will return a list containing the query results, with each element being a tuple containing a row of data.

  1. Close the database connection.
conn.close()

Full code example:

import sqlite3

conn = sqlite3.connect('database.db')
cursor = conn.cursor()
cursor.execute('SELECT * FROM table_name')
result = cursor.fetchall()
conn.close()

for row in result:
    print(row)

Please note that this is just a basic example of connecting to and retrieving data from a SQLite database using the sqlite3 library. If you are using a different type of database (such as MySQL, PostgreSQL, etc.), you will need to use the corresponding library (such as pymysql, psycopg2, etc.) to connect and retrieve data. The specific operations may vary, so please refer to the documentation or sample code of the respective library.

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