How to Get the Auto-Generated ID After Inserting Data in SQLite (Python)

• Import the sqlite3 library.
• Create a connection to your SQLite database.
• Create a cursor object using the cursor() method of the connection.
• Execute the INSERT statement with your data. You can use placeholders (?) for values.
• After executing the insert, access the lastrowid attribute of the cursor object. This attribute holds the ID of the last inserted row.

Here's an example:

import sqlite3

conn = sqlite3.connect("mydatabase.db")
cursor = conn.cursor()

cursor.execute("INSERT INTO users (name, email) VALUES (?, ?)", ("Alice", "[email protected]"))

# Get the ID of the inserted row
user_id = cursor.lastrowid

# Now you can use the user_id

conn.commit()  # Save changes (important!)
conn.close()

Points to Remember:

• lastrowid only works within the current connection and cursor. It won't remember IDs across different connections.
• Make sure to commit the changes (conn.commit()) after inserting the row to ensure the ID is persistent.

Alternative (for future reference):

• SQLite also supports the RETURNING clause in INSERT statements. This can be used to retrieve the inserted row directly, but it's not as commonly used as lastrowid.

import sqlite3

# Connect to the database
conn = sqlite3.connect("mydatabase.db")
cursor = conn.cursor()

# Example 1: Using lastrowid

# Insert data with placeholders
cursor.execute("INSERT INTO users (name, email) VALUES (?, ?)", ("Bob", "[email protected]"))

# Get the ID of the inserted row
user_id_lastrowid = cursor.lastrowid
print("User ID (lastrowid):", user_id_lastrowid)

# Example 2: Using RETURNING clause (less common)

# Insert data with RETURNING clause to get the inserted row directly
cursor.execute("INSERT INTO users (name, email) VALUES (?, ?) RETURNING id", ("Charlie", "[email protected]"))

# Fetch the inserted row (id is the first column)
inserted_user = cursor.fetchone()
user_id_returning = inserted_user[0]
print("User ID (RETURNING):", user_id_returning)

# Commit changes and close connection
conn.commit()
conn.close()

This code demonstrates both methods:

1. Using lastrowid: After inserting data, it retrieves the ID using cursor.lastrowid.
2. Using RETURNING clause: The INSERT statement includes RETURNING id, which returns the inserted row's ID directly. The code then fetches the first column (ID) from the returned row.

1. Using a sequence:

2. Using SELECT last_insert_rowid():

Here's how these methods work:

import sqlite3

conn = sqlite3.connect("mydatabase.db")
cursor = conn.cursor()

# Create a sequence if it doesn't exist
cursor.execute("CREATE SEQUENCE IF NOT EXISTS user_id_seq")

# Insert data referencing the sequence
cursor.execute("INSERT INTO users (name, email) VALUES (?, ?)", ("David", "[email protected]"))

# Get the last inserted ID using sequence
cursor.execute("SELECT last_value FROM user_id_seq")
user_id_sequence = cursor.fetchone()[0]
print("User ID (sequence):", user_id_sequence)

conn.commit()
conn.close()

import sqlite3

conn = sqlite3.connect("mydatabase.db")
cursor = conn.cursor()

# Insert data with RETURNING clause to get the inserted row directly
cursor.execute("INSERT INTO users (name, email) VALUES (?, ?)", ("Emily", "[email protected]") +
                " RETURNING id AS new_id")  # Alias the ID column

# Fetch the ID from the returned row (using alias)
inserted_user = cursor.fetchone()
user_id_returning = inserted_user[0]
print("User ID (last_insert_rowid):", user_id_returning)

conn.commit()
conn.close()

Choosing the right method:

• lastrowid is the simplest and most common approach, but it might not be suitable for multi-threaded environments due to potential race conditions.
• Using a sequence offers more control and avoids race conditions, but it requires additional management of the sequence itself.
• SELECT last_insert_rowid() is similar to lastrowid but allows for integration within the INSERT statement itself.