CS50 Fall 2025 - Lecture 7 - SQL (live, unedited) | CS50

In this CS50 lecture, the speaker introduces SQL (Structured Query Language) as a declarative programming language, contrasting it with procedural languages like C and Python. The session involves collecting real-world data via a Google Form to demonstrate SQL's capabilities. The speaker explains how to download and import CSV data into SQLite, perform CRUD operations (Create, Read, Update, Delete), and optimize queries using indexes. The lecture also covers data modeling, relationships in databases (one-to-one, one-to-many, many-to-many), and potential security vulnerabilities like SQL injection attacks, emphasizing the importance of sanitizing user inputs and using parameterized queries to prevent malicious code execution. The concept of race conditions and transactions are introduced as well.

Outlines

Part 1: Programming Paradigms and Python Data Processing

Part 2: SQL Fundamentals and CRUD Operations

Part 3: Database Design and Relational Modeling

Part 4: Optimization, Integration, and Security

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CS50 Fall 2025 - Lecture 7 - SQL (live, unedited)

CS50

Part 1: Programming Paradigms and Python Data Processing

Introduction to SQL and Declarative Programming

Reading and Processing Data from a CSV File with Python

Counting Language Preferences Using Conditionals and Dictionaries in Python

Part 2: SQL Fundamentals and CRUD Operations

Introduction to Relational Databases and Basic SQL Queries

Advanced SQL Queries: Filtering, Grouping, and Ordering Data

SQL Data Manipulation: Inserting, Updating, and Deleting Data

Part 3: Database Design and Relational Modeling

Database Design and Normalization: Modeling Real-World Data

Exploring a Real-World Database: TV Shows, Ratings, and Genres

Joining Tables and Nested Queries: Retrieving Related Data

Many-to-Many Relationships and Complex Queries: Shows, People, and Stars

Part 4: Optimization, Integration, and Security

Optimizing SQL Queries with Indexes

Combining Python and SQL: Interactivity and SQL Injection Attacks

Race Conditions, Transactions, and Conclusion

CS50 Fall 2025 - Lecture 7 - SQL (live, unedited)

CS50

Part 1: Programming Paradigms and Python Data Processing

10:38Introduction to SQL and Declarative Programming

Introduction to SQL and Declarative Programming

17:13Reading and Processing Data from a CSV File with Python

Reading and Processing Data from a CSV File with Python

27:35Counting Language Preferences Using Conditionals and Dictionaries in Python

Counting Language Preferences Using Conditionals and Dictionaries in Python

Part 2: SQL Fundamentals and CRUD Operations

34:18Introduction to Relational Databases and Basic SQL Queries

Introduction to Relational Databases and Basic SQL Queries

45:56Advanced SQL Queries: Filtering, Grouping, and Ordering Data

Advanced SQL Queries: Filtering, Grouping, and Ordering Data

55:50SQL Data Manipulation: Inserting, Updating, and Deleting Data

SQL Data Manipulation: Inserting, Updating, and Deleting Data

Part 3: Database Design and Relational Modeling

1:03:06Database Design and Normalization: Modeling Real-World Data

Database Design and Normalization: Modeling Real-World Data

1:17:40Exploring a Real-World Database: TV Shows, Ratings, and Genres

Exploring a Real-World Database: TV Shows, Ratings, and Genres

1:33:56Joining Tables and Nested Queries: Retrieving Related Data

Joining Tables and Nested Queries: Retrieving Related Data

1:47:50Many-to-Many Relationships and Complex Queries: Shows, People, and Stars

Many-to-Many Relationships and Complex Queries: Shows, People, and Stars

Part 4: Optimization, Integration, and Security

1:55:22Optimizing SQL Queries with Indexes

Optimizing SQL Queries with Indexes

2:08:42Combining Python and SQL: Interactivity and SQL Injection Attacks

Combining Python and SQL: Interactivity and SQL Injection Attacks

2:28:48Race Conditions, Transactions, and Conclusion

Race Conditions, Transactions, and Conclusion