**Course Title:** SQL Mastery: From Fundamentals to Advanced Techniques **Section Title:** Views, Stored Procedures, and Triggers **Topic:** Write SQL scripts to create views, stored procedures, and triggers.(Lab topic) **Objective:** In this lab topic, you will learn how to write SQL scripts to create views, stored procedures, and triggers, which are essential database objects that help improve data management, encapsulate complex logic, and automate tasks. **Key Concepts:** * Views: Virtual tables that simplify complex queries and provide data abstraction. * Stored Procedures: Reusable blocks of code that perform specific operations. * Triggers: Automated procedures that respond to data changes. **Creating Views:** To create a view, use the `CREATE VIEW` statement. The basic syntax is: ```sql CREATE VIEW [view_name] AS SELECT [column_list] FROM [table_name]; ``` For example: ```sql -- Create a view to display customer data CREATE VIEW customer_data AS SELECT customer_id, first_name, last_name, email FROM customers; ``` To modify a view, use the `ALTER VIEW` statement: ```sql ALTER VIEW [view_name] AS SELECT [new_column_list] FROM [table_name]; ``` To drop a view, use the `DROP VIEW` statement: ```sql DROP VIEW [view_name]; ``` **Creating Stored Procedures:** To create a stored procedure, use the `CREATE PROCEDURE` statement. The basic syntax is: ```sql CREATE PROCEDURE [procedure_name] ([parameter_list]) BEGIN [procedure_body] END; ``` For example: ```sql -- Create a stored procedure to retrieve customer data CREATE PROCEDURE get_customer_data(IN customer_id INT) BEGIN SELECT first_name, last_name, email FROM customers WHERE customer_id = customer_id; END; ``` To execute a stored procedure, use the `CALL` statement: ```sql CALL get_customer_data(123); ``` To modify a stored procedure, use the `ALTER PROCEDURE` statement: ```sql ALTER PROCEDURE [procedure_name] ([new_parameter_list]) BEGIN [new_procedure_body] END; ``` To drop a stored procedure, use the `DROP PROCEDURE` statement: ```sql DROP PROCEDURE [procedure_name]; ``` **Creating Triggers:** To create a trigger, use the `CREATE TRIGGER` statement. The basic syntax is: ```sql CREATE TRIGGER [trigger_name] [trigger_event] ON [table_name] [trigger_body]; ``` For example: ```sql -- Create a trigger to update the order total when an item is added CREATE TRIGGER update_order_total AFTER INSERT ON order_items FOR EACH ROW BEGIN UPDATE orders SET order_total = order_total + NEW.item_price WHERE order_id = NEW.order_id; END; ``` To modify a trigger, use the `ALTER TRIGGER` statement: ```sql ALTER TRIGGER [trigger_name] [trigger_event] ON [table_name] [trigger_body]; ``` To drop a trigger, use the `DROP TRIGGER` statement: ```sql DROP TRIGGER [trigger_name]; ``` **Lab Exercise:** 1. Create a view to display the top 5 products by sales. 2. Create a stored procedure to retrieve customer data by country. 3. Create a trigger to update the inventory level when a product is sold. **Tips and Reminders:** * Use prefixes for your database objects, such as `vw_` for views and `sp_` for stored procedures. * Use indexes to improve query performance. * Test your code thoroughly before deploying it to production. **External Resources:** * MySQL Documentation: [https://dev.mysql.com/doc/](https://dev.mysql.com/doc/) * PostgreSQL Documentation: [https://www.postgresql.org/docs/](https://www.postgresql.org/docs/) * SQL Server Documentation: [https://docs.microsoft.com/en-us/sql/](https://docs.microsoft.com/en-us/sql/) **Do you have questions about this topic? Leave a comment below!** **What's next?** In the next topic, we will cover Introduction to database security concepts. Stay tuned! Remember to keep your questions and comments here for responses, no further discussion boards will be provided for this topic.