This chapter focuses solely on **retrieving records** from a database using SQLAlchemy. You’ll learn how to fetch **single** or **multiple** records efficiently using various querying methods.

### Fetching a Single Record

To retrieve a single record, use `query()` and apply filters. For instance, to find a product by its name:  

```python
product = session.query(Product).filter(Product.name == "Laptop").first()
```

Here, `.filter(Product.name == "Laptop")` selects products with the name "Laptop," and `.first()` returns the first matching record or `None`.

### Fetching Multiple Records

To retrieve multiple records, combine `filter()` with `.all()`. For example, to list all products:  

```python
products = session.query(Product).all()
```

To filter products, e.g., those priced above $1000, modify the query:  

```python
expensive_products = session.query(Product).filter(Product.price > 1000).all()
```

### Using get() for Primary Key Lookups

For efficient retrieval by primary key, use `get()`. For example, fetching a product with ID 1:  

```python
product = session.query(Product).get(1)
```

### Limiting Results

To limit the number of records retrieved, apply `.limit()`. For example, to fetch the first 3 products:  

```python
limited_products = session.query(Product).limit(3).all()
```

By mastering these techniques, you’ll efficiently retrieve the data you need, whether it’s a single record, multiple filtered results, or a limited subset.

"Databases in Python" is a hands-on course designed to teach you the fundamentals of working with databases using Python, focusing on the sqlite3 library and SQLAlchemy. You’ll learn how to store, modify, and retrieve data, build efficient queries, and configure databases for your projects. The course covers both SQL basics and the ORM (Object-Relational Mapping) approach, which allows you to interact with databases through Python objects. This course is perfect for beginners looking to deepen their skills in data management, application development, and information handling.

Whether you're new to databases or want to master SQLite, this course will teach you the essentials. You'll learn data management, and how to use SQLite effectively.

CRUD (Create, Read, Update, Delete) are the foundational operations in working with databases. This section is your gateway to mastering these core database functions.

In the "CRUD Operations" section, we will delve into creating, retrieving, updating, and deleting data in a database. You will gain the skills needed to interact with databases effectively, making it an essential tool for your software development journey.

Congratulations on reaching the final section of this course! You've come a long way in your journey to learn and master the content covered.

In this concluding section, we'll summarize key takeaways, reinforce your knowledge, and provide guidance on what you can do next. You've acquired valuable skills and insights, and now it's time to reflect on your achievements and explore how to apply your newfound knowledge effectively.



Learn how to interact with databases in Python using SQLAlchemy, a powerful Object-Relational Mapping (ORM) tool. This section covers setting up connections, defining models, and performing essential CRUD operations (Create, Read, Update, Delete). You'll discover how to write cleaner, more efficient code without relying on raw SQL queries. Mastering SQLAlchemy will streamline database management and enhance the scalability of your Python applications.

Reading from DB

Fetching a Single Record

Fetching Multiple Records

Using get() for Primary Key Lookups