![SQLite Methods:
Here's a brief explanation of the connect, cursor, execute, and close methods in
the context of SQLite with the sqlite3 module in Python:
1.connect Method:
• Purpose: Establishes a connection to an SQLite database.
• Syntax:
connect(database[, timeout, detect_types, isolation_level, check_same_thread,
factory, cached_statements, uri])
• Parameters:
database: The name of the SQLite database file.
timeout (optional): Timeout in seconds for blocking operations.
detect_types (optional): Determines if types should be detected.
isolation_level (optional): Isolation level for transactions.
check_same_thread (optional): Check if the same thread created the
connection.
factory (optional): Custom class for creating a cursor.
cached_statements (optional): Number of cached statements per
connection.
uri (optional): If True, interpret the database parameter as a URI.](https://image.slidesharecdn.com/pythonsqlite3-240119172640-017e00cd/85/Python-SQLite3-pptx-6-320.jpg)
![SQLite Methods:
2. cursor Method:
• Purpose: Creates a cursor object used to execute SQL
commands and manage query results.
• Syntax:
cursor()
• Parameters: None
• Example:
cursor = conn.cursor()
3. execute Method:
• Purpose: Executes an SQL statement.
• Syntax:
execute(sql[, parameters])
• Parameters:
sql: The SQL statement to be executed.
parameters (optional): A tuple or dictionary containing
parameters for the SQL statement.](https://image.slidesharecdn.com/pythonsqlite3-240119172640-017e00cd/85/Python-SQLite3-pptx-7-320.jpg)
Python SQLite3.pptx
- 2. What is sqlite3 module in Python? SQLite3, which is a lightweight database engine, uses SQL as its query language, and Python's sqlite3 module allows you to execute SQL commands directly. The four fundamental operations of persistent storage are Create, Read, Update, and Delete (CRUD).
- 3. Here's a brief overview of using the sqlite3 module: 1. Connecting to a Database: import sqlite3 # Connect to a database (or create it if it doesn't exist) conn = sqlite3.connect('example.db') 2. Creating a Cursor: A cursor is used to execute SQL statements and fetch results. # Create a cursor object cursor = conn.cursor()
- 4. Here's a brief overview of using the sqlite3 module: 3. Creating a Table: # Create a table if it doesn't exist cursor.execute(''' CREATE TABLE IF NOT EXISTS users ( id INTEGER PRIMARY KEY, name TEXT, age INTEGER ) ''') 4. Inserting Data: # Insert data into the table cursor.execute("INSERT INTO users (name, age) VALUES (?, ?)", (‘vikas', 29)) cursor.execute("INSERT INTO users (name, age) VALUES (?, ?)", (‘ram', 30))
- 5. Here's a brief overview of using the sqlite3 module: 5. Committing Changes: # Commit the changes conn.commit() 6. Querying Data: # Query data from the table cursor.execute("SELECT * FROM users") rows = cursor.fetchall() # Display the queried data for row in rows: print(row) 7. Closing Resources: # Close the cursor and connection cursor.close() conn.close()
- 6. SQLite Methods: Here's a brief explanation of the connect, cursor, execute, and close methods in the context of SQLite with the sqlite3 module in Python: 1.connect Method: • Purpose: Establishes a connection to an SQLite database. • Syntax: connect(database[, timeout, detect_types, isolation_level, check_same_thread, factory, cached_statements, uri]) • Parameters: database: The name of the SQLite database file. timeout (optional): Timeout in seconds for blocking operations. detect_types (optional): Determines if types should be detected. isolation_level (optional): Isolation level for transactions. check_same_thread (optional): Check if the same thread created the connection. factory (optional): Custom class for creating a cursor. cached_statements (optional): Number of cached statements per connection. uri (optional): If True, interpret the database parameter as a URI.
- 7. SQLite Methods: 2. cursor Method: • Purpose: Creates a cursor object used to execute SQL commands and manage query results. • Syntax: cursor() • Parameters: None • Example: cursor = conn.cursor() 3. execute Method: • Purpose: Executes an SQL statement. • Syntax: execute(sql[, parameters]) • Parameters: sql: The SQL statement to be executed. parameters (optional): A tuple or dictionary containing parameters for the SQL statement.
- 8. SQLite Methods: Example: cursor.execute("INSERT INTO users (name, age) VALUES (?, ?)", (‘Vikas', 29)) 4. close Method: • Purpose: Closes the database connection and the cursor. • Syntax: close() Example: conn.close()
- 9. Connect to Database: To connect to an SQLite database using the sqlite3 module in Python, you can use the connect method. Example: import sqlite3 # Connect to the SQLite database (creates the database if it doesn't exist) conn = sqlite3.connect('example.db') # Create a cursor cursor = conn.cursor() # Perform database operations here # Close the connection when done conn.close()
- 10. Create Table: Below is an example of how to create a table in SQLite using the sqlite3 module in Python: import sqlite3 # Connect to the SQLite database (creates the database if it doesn't exist) conn = sqlite3.connect('example.db') # Create a cursor cursor = conn.cursor() # Create a table named 'users' cursor.execute('''CREATE TABLE IF NOT EXISTS users ( id INTEGER PRIMARY KEY, name TEXT NOT NULL, age INTEGER )''') # Commit the changes conn.commit() # Close the connection conn.close()
- 11. • In the above example: We connect to the SQLite database using sqlite3.connect('example.db'). We create a cursor using conn.cursor(). We use the execute method to run an SQL statement that creates a table named 'users'. The table has three columns: 'id', 'name', and 'age'. The 'id' column is an INTEGER and is set as the primary key. The 'name' column is of type TEXT and cannot be NULL. The 'age' column is of type INTEGER. The IF NOT EXISTS clause ensures that the table is only created if it doesn't already exist. We commit the changes to the database using conn.commit(). Finally, we close the connection using conn.close().
- 12. • Operations on Tables- Insert, Select, Update. Delete and Drop Records. Insert: • In this example: • We connect to the SQLite database and create a cursor as usual. • We create a table named 'users' if it doesn't exist, with columns 'id', 'name', and 'age'. • We define a list users_data containing tuples of name and age for multiple users. • We use the executemany method to insert multiple records into the 'users' table in a single operation. This is more efficient than using execute multiple times. • After inserting the records, we commit the changes to the database. • We then select and print all records from the 'users' table to verify the successful insertion.
- 13. • Operations on Tables- Insert, Select, Update. Delete and Drop Records. Select: • In this example: • We connect to the SQLite database and create a cursor as usual. • We create a table named 'users' if it doesn't exist, with columns 'id', 'name', and 'age'. • We insert records into the 'users' table using the executemany method. • We commit the changes to the database. • We use the SELECT * FROM users SQL statement to select all records from the 'users' table. • We fetch all rows using fetchall() and print them
- 14. • Operations on Tables- Insert, Select, Update. Delete and Drop Records. Update: • In this example: • We connect to the SQLite database and create a cursor as usual. • We create a table named 'users' if it doesn't exist, with columns 'id', 'name', and 'age'. • We insert records into the 'users' table using the executemany method. • We commit the changes to the database. • We select and print all records from the 'users' table before the update. • We use the UPDATE statement to modify the age of a user ('vikas') to 29. • We commit the changes to the database. • We select and print all records from the 'users' table after the update.
- 15. • Operations on Tables- Insert, Select, Update. Delete and Drop Records. Delete: • In this example: • We connect to the SQLite database and create a cursor as usual. • We create a table named 'users' if it doesn't exist, with columns 'id', 'name', and 'age'. • We insert records into the 'users' table using the executemany method. • We commit the changes to the database. • We select and print all records from the 'users' table before the delete. • We use the DELETE statement to remove a specific user record ('vikas') from the 'users' table. • We commit the changes to the database. • We select and print all records from the 'users' table after the delete.
- 16. • Operations on Tables- Insert, Select, Update. Delete and Drop Records. Drop Records: • We connect to the SQLite database and create a cursor. • We create a table named 'users' if it doesn't exist. • We insert records into the 'users' table using the executemany method. • We commit the changes to the database. • We select and print all records from the 'users' table before dropping. • We use the DROP TABLE statement to drop the entire 'users' table, effectively removing all records. • We commit the changes to the database. • We attempt to select from the 'users' table after dropping, resulting in an OperationalError since the table no longer exists.