Optimize Query Performance with SQL Denormalization

Denormalizing for Performance Optimization

Write a SQL query to denormalize a database for improved query performance.

Solution:

-- Normalized tables.
CREATE TABLE Customers (
    CustomerID INT PRIMARY KEY,
    CustomerName VARCHAR(100)
);

CREATE TABLE Orders (
    OrderID INT PRIMARY KEY,
    CustomerID INT,
    OrderDate DATE,
    FOREIGN KEY (CustomerID) REFERENCES Customers(CustomerID)
);

-- Denormalized table for faster reporting.
CREATE TABLE CustomerOrders_Denormalized AS
SELECT o.OrderID, c.CustomerName, o.OrderDate
FROM Orders o
JOIN Customers c ON o.CustomerID = c.CustomerID;

Explanation:

• Purpose of the Query :
• The goal is to denormalize a database to improve query performance for reporting purposes.
• Key Components :
• CustomerOrders_Denormalized: Combines customer and order details into a single table.
• Reduces the need for joins during reporting queries.
• Why Denormalize? :
• Denormalization improves read performance by reducing the number of joins.
• It is useful for read-heavy workloads like dashboards.
• Real-World Application :
• In analytics systems, denormalized tables speed up complex reports.

Notes:

• Denormalization increases storage requirements and update complexity.
• Use it sparingly and only for specific use cases.
• Important Considerations:
• Maintain synchronization between normalized and denormalized tables.

For more Practice: Solve these Related Problems:

• Write a SQL query to denormalize a database by combining customer and order details into a single table for faster reporting.
• Write a SQL query to create a denormalized table for a dashboard displaying product sales and customer feedback.
• Write a SQL query to denormalize a database by merging supplier and product details for improved query performance.
• Write a SQL query to design a denormalized table for a report showing employee performance and department metrics.

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