Python Delete from SQLite Table

Learn to delete data from an SQLite table using Python. You’ll learn how to use Python’s built-in module sqlite3 to delete data from the SQLite table.

Goals of this lesson

• Delete a single and multiple rows, all rows, a single column, and multiple columns from the SQLite table using Python
• Use a Python parameterized query to provide value at runtime to the SQLite delete query
• Execute a bulk delete using a single query

Prerequisite

If a table is not present in your SQLite database, then please refer to the following articles: –

• Create SQLite table from Python.
• Insert data into SQLite Table from Python

Steps to delete a single row from SQLite table

As of now, the SqliteDb_developers table contains six rows, so let’s remove the developer whose id is 6.

Example

import sqlite3

def deleteRecord():
    try:
        sqliteConnection = sqlite3.connect('SQLite_Python.db')
        cursor = sqliteConnection.cursor()
        print("Connected to SQLite")

        # Deleting single record now
        sql_delete_query = """DELETE from SqliteDb_developers where id = 6"""
        cursor.execute(sql_delete_query)
        sqliteConnection.commit()
        print("Record deleted successfully ")
        cursor.close()

    except sqlite3.Error as error:
        print("Failed to delete record from sqlite table", error)
    finally:
        if sqliteConnection:
            sqliteConnection.close()
            print("the sqlite connection is closed")

deleteRecord()

Output:

Note: If you are doing multiple delete operations and wanted to revert your change in case of failure of any operations, use the rollback() function of the connection class to revert the changes. Use rollback() function in except block.

Use Python Variable in a query to Delete Row from SQLite table

Most of the time, we need to delete a row from an SQLite table where the id passed at runtime. For example, when a user cancels his/her subscription, we need to delete the entry from a table as per the user id. In such cases, It is always best practice to use a parameterized query.

The parameterized query uses placeholders (?) inside SQL statements that contain input from users. It helps us to delete runtime values and prevent SQL injection concerns.

import sqlite3

def deleteSqliteRecord(id):
    try:
        sqliteConnection = sqlite3.connect('SQLite_Python.db')
        cursor = sqliteConnection.cursor()
        print("Connected to SQLite")

        sql_update_query = """DELETE from SqliteDb_developers where id = ?"""
        cursor.execute(sql_update_query, (id,))
        sqliteConnection.commit()
        print("Record deleted successfully")

        cursor.close()

    except sqlite3.Error as error:
        print("Failed to delete reocord from a sqlite table", error)
    finally:
        if sqliteConnection:
            sqliteConnection.close()
            print("sqlite connection is closed")

deleteSqliteRecord(5)

Output

Let’s understand the above example

• We used the parameterized query to accept developer id at runtime using a placeholder(?) for the id column
• Next, We then prepared data tuple by using Python variables.
• Next, we passed the SQL delete query and data tuple to a cursor.execute() method.
• In the end, we made our changes permanent into the database using a commit() method of a connection class.

Delete multiple rows from SQLite table

In the above example, we have used execute() method of cursor object to update a single record, but sometimes, we need to delete an N-number of rows. For example, You want to delete employee data from the developer’s table who left the organization.

Instead of executing a delete query repeatedly to delete each record, you can perform the bulk delete operation in a single query using the cursor.executemany() method.

The executemany(query, seq_param) method accepts two parameters a SQL query and a list of records to delete.

In this example, we are removing three rows.

import sqlite3

def deleteMultipleRecords(idList):
    try:
        sqliteConnection = sqlite3.connect('SQLite_Python.db')
        cursor = sqliteConnection.cursor()
        print("Connected to SQLite")
        sqlite_update_query = """DELETE from SqliteDb_developers where id = ?"""

        cursor.executemany(sqlite_update_query, idList)
        sqliteConnection.commit()
        print("Total", cursor.rowcount, "Records deleted successfully")
        cursor.close()

    except sqlite3.Error as error:
        print("Failed to delete multiple records from sqlite table", error)
    finally:
        if sqliteConnection:
            sqliteConnection.close()
            print("sqlite connection is closed")

idsToDelete = [(4,), (3,)]
deleteMultipleRecords(idsToDelete)

Output

Connected to SQLite
Total 2 Records deleted successfully
sqlite connection is closed

Let’s understand the above example

• We prepared SQLite parameterized delete query with a single placeholder and then created a list of Ids to remove in tuple format.
• Each element of a list is nothing but a tuple for each row. Each tuple contains the id of a developer. Here we created three tuples, so we are deleting three rows.
• Next, we called a executemany() method to delete multiple rows from the SQLite table.
• To get to know the number of records updated, we used a cursor.rowcount method.

Next Steps:

To practice what you learned in this article, Please solve a Python Database Exercise project to Practice and master the Python Database operations.