Software development evolves occasionally, resulting in developers having to decide which approach or methodology is best and suitable to adhere to. One of the fundamental decisions of a developer is how to integrate and interact with database systems effectively.

Databases play a pivotal role in storing, managing, and retrieving data. To interact with databases, developers have two primary choices: database drivers and Object-Relational Mappers (ORM).

Here, you'll learn about database drivers and Object-Relational Mappers (ORM), shedding light on their strengths, weaknesses, and the balance developers must strike when making a decision.

Database Drivers: A Low-Level Connection

Database drivers, often called database connectors or client libraries, are designed to establish connections to a database, send SQL queries to the database server, and retrieve the results. They act as intermediaries between your application and the database management system (DBMS).

Database drivers are conceptually simple. They rely on SQL (Structured Query Language) for interacting with the database, which means you have full control over the SQL statements you write. This level of control can be advantageous when optimizing database performance, dealing with complex queries, or working with specific features of a database system.

However, it also means that developers using database drivers must write and manage raw SQL queries, which can be error-prone and lead to potential security vulnerabilities like SQL injection if not handled carefully. Furthermore, database drivers are typically tied to a specific DBMS, making it less portable across different database systems.

Why Use Database Drivers?

Here, you'll see situations where using database drivers shines and why they are the preferred choice in certain use cases.

• Performance-Critical Applications: Database drivers are invaluable for performance-critical applications like high-frequency trading systems and gaming servers, where milliseconds matter, and optimizing database interactions is essential for high throughput and low latency.

• Customized Query Optimization: Database drivers offer the flexibility to craft customized, database-specific SQL queries, making them ideal for implementing advanced search functionality like full-text search or optimizing queries for performance in data warehousing projects dealing with large datasets.

• Legacy Database Systems: Database drivers are indispensable when interfacing with legacy or less common database systems, such as mainframe databases with unique protocols or niche industry-specific databases lacking robust ORM support.

• Custom Database Features: Database drivers are often preferred when an application relies on database-specific features like geospatial extensions or stored procedures, enabling direct interaction with these specialized functionalities.

• Data Migration and ETL (Extract, Transform, Load) Tasks: Database drivers are indispensable when performing data migration, ETL processes, or bulk data loading. They offer the performance and control needed for such operations, often involving transferring large data volumes between systems.

Programming Languages and Database Drivers

Here are some common programming languages and their corresponding database drivers:

1. Python: psycopg2 for PostgreSQL, mysql-connector-python for MySQL, and pymongo for MongoDB.

2. JavaScript (Node.js): mysql2 for MySQL, pg for PostgreSQL, and mongodb for MongoDB.

3. PHP: has built-in support for several databases, including MySQL (mysqli and PDO), PostgreSQL (PDO), and MongoDB (mongodb).

4. Ruby: pg for PostgreSQL, mysql2 for MySQL, and mongo for MongoDB.

These are just a few examples, and many more programming languages and database drivers are available for various databases and systems.

Using Database Driver in Python With SQLite

Python includes sqlite3 as part of its standard library, making it an excellent choice for lightweight database interactions. In this section, you will explore how to use sqlite3 to interact with a database (SQLite3) in Python.

Setting Up the Database

First, you'll create a SQLite database and define a simple schema for a movie database.

## script.py

import sqlite3

# Establish a connection to the SQLite database 
# (or create a new one if it doesn't exist)
connection = sqlite3.connect('movie_db.sqlite')

# Create a cursor
cursor = connection.cursor()

# Create a table for movies
cursor.execute('''
    CREATE TABLE IF NOT EXISTS movies (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        title TEXT NOT NULL,
        year INTEGER,
        genre TEXT
    )
''')

# Commit the changes and close the cursor
connection.commit()
cursor.close()

Run the code above from a script.

Inserting Data Into the Database

Using the IDLE, insert some movie data into your database.

## IDLE

cursor = connection.cursor()

# Insert movie data
cursor.execute("INSERT INTO movies (title, year, genre) VALUES (?, ?, ?)", ("Inception", 2010, "Science Fiction"))
cursor.execute("INSERT INTO movies (title, year, genre) VALUES (?, ?, ?)", ("The Shawshank Redemption", 1994, "Drama"))

connection.commit()
cursor.close()

Querying Data From the Database

You can now query the data from the database. Here's an example of fetching all movie data.

## IDLE

cursor = connection.cursor()

# Fetch all movies
cursor.execute("SELECT * FROM movies")
movies = cursor.fetchall()

# Display the movie data
for movie in movies:
    print("Movie:", movie[1])
    print("Year:", movie[2])
    print("Genre:", movie[3])
    print()

cursor.close()

Run a SELECT query to get data out of the database, then iterate through the output and print it.

Updating and Deleting Data From the Database

Let's update a movie's genre and delete another movie from the database.

## IDLE

cursor = connection.cursor()

# Update a movie's genre
cursor.execute("UPDATE movies SET genre = ? WHERE title = ?", ("Thriller", "Inception"))

# Delete a movie
cursor.execute("DELETE FROM movies WHERE id = ?", (2))

connection.commit()
cursor.close()

Run the select query to see the updated and deleted data.

You can expand upon this foundation to build a more complex database or adapt it to suit your project needs.

As you've seen, using a database driver lets you achieve fine-grained control over database interactions and SQL commands/queries while optimizing performance, particularly in scenarios involving complex queries or database-specific features.

Drawbacks of Database Drivers

Here are some of the common drawbacks associated with using database drivers:

1. Low-Level Complexity: Database drivers require developers to write SQL queries manually, which can be error-prone and lead to SQL injection vulnerabilities if not handled carefully. This low-level approach also means developers must explicitly manage database connections, transactions, and error handling.

2. Database Portability: Database drivers are often specific to a particular database system, such as MySQL, PostgreSQL, or Oracle. If you switch to a different database system, you may need to rewrite significant portions of your code to accommodate the new driver.

3. Maintenance Overhead: Managing database connections, connection pooling, and resource cleanup can become complex and time-consuming, especially in applications with high concurrency or long-running processes, leading to increased maintenance overhead.

4. Limited Abstraction: Database drivers provide minimal abstraction over the underlying database, which means developers must have a deep understanding of the database system and SQL language. This can be challenging for newcomers or those less familiar with database intricacies.

5. Cross-Platform Compatibility: Database drivers may only sometimes offer consistent functionality and behaviour across different programming languages or platforms. This can lead to platform-specific code and compatibility issues.

ORMs: Bridging the Object-Relational Divide

ORM frameworks are high-level libraries or tools that provide an abstraction layer between your application's code and the database. They map database tables to object-oriented code representations, abstract away the intricacies of SQL queries, and provide a way to interact with the database using code that resembles the structure of the programming language.

While ORMs offer convenience and productivity gains, they are only sometimes the best choice for all scenarios. They introduce an additional layer of abstraction, which can lead to some performance overhead, especially when dealing with complex queries or large datasets. Additionally, ORMs may have a learning curve and may not support all database-specific features.

Why Settle for ORMs?

ORMs have revolutionized how developers work with databases by providing an elegant and efficient abstraction layer.

• Reduced Boilerplate Code: ORMs eliminate the need for manually writing SQL queries for common database operations. This means less boilerplate code cluttering your application and faster development.

• Abstraction of Database Complexity: ORMs abstract the intricacies of database systems, allowing developers to work with objects and entities rather than dealing directly with tables and SQL statements. This abstraction simplifies code and reduces the learning curve.

• Rapid Prototyping: Developers can quickly prototype and iterate on database-driven applications, thanks to the intuitive nature of ORMs. This is particularly beneficial during the early stages of a project.

• Simplified CRUD Operations: ORMs excel at streamlining CRUD (Create, Read, Update, Delete) operations.

• Data Modeling and Relationships: ORMs offer valuable tools for modelling intricate data relationships, including entity relationships (e.g., one-to-many, many-to-one), data validation, automated schema generation, and streamlining application database management.

Popular ORM Libraries

Several ORM frameworks cater to different programming languages and ecosystems. Here are a few notable ones:

• Hibernate: Hibernate is a widely used ORM framework for Java applications. It offers robust features for mapping Java objects to relational database tables and supports various database systems.

• Entity Framework: Developed by Microsoft, Entity Framework is the go-to ORM for .NET applications. It seamlessly integrates with the .NET ecosystem and simplifies data access for C# developers.

• Django ORM: Django, a popular Python web framework, includes a built-in ORM that simplifies database interaction. It promotes rapid development while maintaining flexibility for complex applications.

• Sequelize: Sequelize is a Node.js ORM that supports multiple SQL-based databases. It offers a promise-based API for working with databases asynchronously.

• SQLAlchemy: SQLAlchemy is a Python ORM known for its flexibility and support for multiple database systems. It provides both a high-level ORM and a lower-level SQL expression language.

Working With ORMs in Python

Here, you will focus on SQLAlchemy and demonstrate how to set up and use it in a Python project.

Installing SQLAlchemy

To get started with SQLAlchemy, you can install it using pip:

pip install SQLAlchemy

Defining Database Models

In SQLAlchemy, you define database models as Python classes. Each class represents a table in the database, and its attributes represent its columns.

## script.py

from sqlalchemy import Column, Integer, String
from sqlalchemy.orm import DeclarativeBase
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker


class Base(DeclarativeBase):
    pass


class Movie(Base):
    __tablename__ = 'movies'

    id = Column(Integer, primary_key=True)
    title = Column(String(255), nullable=False)
    release_year = Column(Integer)

In the code above, you define a model, Movie, with a corresponding table definition.

Create an SQLAlchemy Engine and Session

Using the create_engine method, create an Engine that makes a new database connection. The sessionmaker method creates a Session that lets you use the Engine to interact with the database.

## script.py

# Create an SQLAlchemy engine and session
engine = create_engine("sqlite:///lite.db", echo=True)
Base.metadata.create_all(engine)

Session = sessionmaker(bind=engine)
session = Session()

Notice how SQLAlchemy executes the raw SQL command/queries for you while providing you with an easy-to-use interface/API similar to Python language features.

Creating Records in the Database

By simply initializing the model class (Movie) with the proper parameters and calling the add method on the object followed by the commit method, you can add new records to the database.

## IDLE

# Create a new movie record
new_movie = Movie(title='Inception', release_year=2010)
session.add(new_movie)
session.commit()

SQL command executed behind the scenes for you.

Reading Records From the Database

The code below retrieves a movie from the database using it's title.

## IDLE

# Query a movie by title
movie = session.query(Movie).filter_by(title='Inception').first()
print(f'Title: {movie.title}, Release Year: {movie.release_year}')

Updating Records in the Database

After retrieving a record, you can update a record or its attribute by assigning new values to the object instance attribute.

## IDLE

# Update a movie's release year
movie.release_year = 2011
session.commit()

You can run the read command to see the updated record, as previously shown.

Deleting Records From the Database

You can delete an existing record from the database using the session delete method.

## IDLE

# Delete a movie record
session.delete(movie)
session.commit()

Trying to retrieve a deleted or nonexistent record will return a None value.

Here, you've seen how ORMs capitalize on the concept of Object Oriented Programming and abstract away the need to deal with raw SQL commands/queries while providing an interface/API similar to the programming language to work with.

Drawbacks of ORMs

Here are some common drawbacks associated with using ORMs:

1. Performance Overhead: The layer of abstraction that ORMs add between the application and the database might slow down performance, especially in scenarios where complex queries or bulk data operations are required. ORM-generated queries may not always be as efficient as hand-optimized SQL queries.

2. Learning Curve: Using an ORM effectively can take time, particularly for new developers. Understanding how to define models, work with relationships, and express complex queries using the ORM's query language can be challenging.

3. Loss of Control: ORMs abstract many database details, which can sometimes lead to a loss of control over the underlying database. Advanced database-specific optimizations or using certain features may be challenging to implement through an ORM.

4. Overhead from Abstraction: The abstraction provided by ORMs can introduce overhead in terms of object-relational mapping, resulting in slower query execution compared to hand-tuned SQL queries in certain scenarios.

5. Complexity of Mapping: Mapping complex data relationships, especially in scenarios involving many-to-many relationships or inheritance hierarchies, can be complex and require significant configuration in the ORM.

6. Schema Management: While ORMs can generate database schemas based on the application's data models, they may not handle all database schema changes gracefully, especially in complex scenarios. Manual intervention may be required for advanced schema management.

Choosing Wisely: Decision-Making Criteria

Deciding whether to use database drivers or Object-Relational Mappers (ORMs) in your project is a critical decision that should align with your project's requirements, team expertise, and performance needs.

1. Project Requirements: Consider your project's complexity, database type, and data modelling needs when deciding between drivers and ORMs.

2. Team Expertise: Factor in your development team's familiarity with ORMs or drivers and the associated learning curve.

3. Performance Needs: Examine whether drivers or ORMs are a better fit for your application's performance requirements, such as throughput and latency.

4. Project Size and Complexity: Choose based on your project's scale and long-term maintenance requirements.

5. Flexibility and Adaptability: Decide based on your application's need for flexibility in handling database schema changes.

6. Ecosystem and Considerations: Consider the programming language and existing libraries used in your project, which may influence your choice between drivers and ORMs.

Conclusion

When interacting with a database, choosing between employing database drivers or embracing Object-Relational Mappers (ORMs) is a pivotal decision that shapes the efficiency and maintainability of your application. The key takeaway from this exploration is that there's no universal answer; choosing revolves around comprehending your project's distinctive demands and selecting the tool that aligns most harmoniously with those needs...