Pandas with SQL databases - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of using pandas with SQL databases?

To easily read data from SQL databases into pandas DataFrames and write DataFrames back to SQL tables for analysis and manipulation.

beginner

Which pandas function is used to read data from a SQL database into a DataFrame?

The function pandas.read_sql() or pandas.read_sql_query() is used to read SQL query results into a DataFrame.

beginner

How do you write a pandas DataFrame to a SQL table?

Use the DataFrame.to_sql() method, specifying the table name and a database connection.

intermediate

What is needed to connect pandas to a SQL database?

A database connection object, often created using libraries like sqlite3, SQLAlchemy, or database-specific connectors.

intermediate

Why might you prefer using SQL queries inside pandas instead of loading entire tables?

Using SQL queries lets you select only the needed data, reducing memory use and speeding up data loading.

Which pandas function reads SQL query results into a DataFrame?

A read_sql_query()

B read_csv()

C to_sql()

D read_excel()

read_sql_query() reads SQL query results into a DataFrame. to_sql() writes DataFrames to SQL tables.

What argument is required to write a DataFrame to a SQL table using to_sql()?

A File path

B Table name

C SQL query

D Column names

You must provide the table name where the DataFrame will be saved.

Which library is commonly used to create a database connection for pandas to use?

A Requests

B NumPy

C Matplotlib

D SQLAlchemy

SQLAlchemy is a popular library to create database connections for pandas.

Why use SQL queries inside pandas instead of loading whole tables?

A To avoid using DataFrames

B To make data bigger

C To select only needed data and save memory

D To skip data cleaning

SQL queries help select only the data you need, which saves memory and speeds up processing.

What does read_sql() require as input?

A SQL query or table name and a database connection

B File path only

C DataFrame object

D List of columns

read_sql() needs a SQL query or table name and a database connection to fetch data.

Explain how you would load data from a SQL database into a pandas DataFrame.

Think about the connection and the function to run SQL inside pandas.

Describe the steps to save a pandas DataFrame back into a SQL database table.

Focus on the method used on the DataFrame and what information it needs.