SQL Server Views In Transportation Industry

SQL Server Views are virtual tables that provide developers with a more efficient and user-friendly way to access data stored in the database. Views can simplify the way data is accessed by providing a consistent, controlled, and secure way of accessing the underlying tables, while hiding the complexity of the database structure. In this blog, we will delve into the different types of SQL Server Views and how they can be utilized in the transportation industry. With views, developers can create customized data views tailored to specific use cases, providing a more streamlined and efficient approach to data management. Whether you’re working in the transportation industry or any other sector, understanding SQL Server Views can help you improve your data management and streamline your application development process.

Agenda

1. Introduction to SQL Server Views
2. Types of SQL Server Views
3. Real-World Example Questions in the Transportation Industry
4. Most Commonly Asked Interview Question
5. Conclusion

Introduction to SQL Server Views

SQL Server Views are virtual tables that can be used to simplify the way you access data stored in the database. Views can provide a consistent, controlled, and secure way of accessing the underlying tables, hiding the complexity of the database structure. In this blog, we will discuss the different types of SQL Server Views and how they can be used in the transportation industry.

Types of SQL Server Views

SQL Server Views can be divided into three main categories: Simple View, Complex View, and Indexed View.

Simple View

A simple view is a SELECT statement that can be used to retrieve data from one or more tables. The SELECT statement can include a WHERE clause, aggregate functions, and any other SQL command that can be used in a SELECT statement. Here is an example of a simple view in the transportation industry:

CREATE VIEW vw_transportation_deliveries
AS
SELECT delivery_id, delivery_date, delivery_destination, delivery_status
FROM deliveries
WHERE delivery_status = 'Delivered'

In this example, we are creating a view vw_transportation_deliveries that retrieves all the deliveries with a status of “Delivered.”

Complex View

A complex view is a SELECT statement that combines data from multiple tables, using joins, and any other SQL command that can be used in a SELECT statement. Here is an example of a complex view in the transportation industry:

CREATE VIEW vw_transportation_delivery_details
AS
SELECT d.delivery_id, d.delivery_date, d.delivery_destination, d.delivery_status,
       v.vehicle_number, v.vehicle_type, v.vehicle_capacity
FROM deliveries d
INNER JOIN vehicles v ON d.vehicle_id = v.vehicle_id

In this example, we are creating a view vw_transportation_delivery_details that retrieves data from two tables, deliveries and vehicles, based on the vehicle_id field.

Indexed View

An indexed view is a view that has a clustered index. This type of view is useful when you need to improve query performance. Here is an example of an indexed view in the transportation industry:

CREATE VIEW vw_transportation_delivery_summary
WITH SCHEMABINDING
AS
SELECT delivery_destination, SUM(delivery_weight) AS total_delivery_weight
FROM deliveries
GROUP BY delivery_destination

In this example, we are creating a view vw_transportation_delivery_summary that retrieves the sum of delivery weight for each delivery destination. The WITH SCHEMABINDING option is used to ensure that the view definition cannot be changed. We are also creating a clustered index `idx_vw_transportation_delivery_summary` on the view, which will help improve the query performance when accessing this view.

Real-World Example Questions in the Transportation Industry

Script to generate tables and records:

-- create the delivery_destinations table 
CREATE TABLE delivery_destinations ( 
  destination_id INT PRIMARY KEY IDENTITY(1, 1), 
  destination_name VARCHAR(50), 
  city VARCHAR(50), 
  state VARCHAR(50) 
); 

-- insert sample data into the delivery_destinations table 
INSERT INTO delivery_destinations (destination_name, city, state) 
VALUES 
  ('Destination A', 'City A', 'State A'), 
  ('Destination B', 'City B', 'State B'), 
  ('Destination C', 'City C', 'State C'), 
  ('Destination D', 'City D', 'State D'), 
  ('Destination E', 'City E', 'State E'); 

-- create the deliveries table 
CREATE TABLE deliveries ( 
  delivery_id INT PRIMARY KEY IDENTITY(1, 1), 
  delivery_destination INT, 
  delivery_date DATE, 
  delivery_start_time DATETIME, 
  delivery_end_time DATETIME, 
  FOREIGN KEY (delivery_destination) REFERENCES delivery_destinations (destination_id) 
); 

-- insert sample data into the deliveries table 
INSERT INTO deliveries (delivery_destination, delivery_date, delivery_start_time, delivery_end_time) 
VALUES 
  (1, '2022-01-01', '2022-01-01 10:00:00', '2022-01-01 11:00:00'), 
  (2, '2022-01-02', '2022-01-02 09:00:00', '2022-01-02 10:00:00'), 
  (3, '2022-01-03', '2022-01-03 08:00:00', '2022-01-03 09:00:00'), 
  (4, '2022-01-04', '2022-01-04 07:00:00', '2022-01-04 08:00:00'), 
  (1, '2022-01-05', '2022-01-05 06:00:00', '2022-01-05 07:00:00'), 
  (2, '2022-01-06', '2022-01-06 05:00:00', '2022-01-06 06:00:00'), 
  (3, '2022-01-07', '2022-01-07 04:00:00', '2022-01-07 05:00:00'), 
  (4, '2022-01-08', '2022-01-08 03:00:00', '2022-01-08 04:00:00');

1.  Write a query to retrieve the titles and release year of all movies that were released in the years 2000 or later, sorted by release year in ascending order.

CREATE VIEW vw_top_5_delivery_destinations AS 
WITH CTE AS ( 
SELECT 
  delivery_destination, 
  COUNT(delivery_id) AS delivery_count 
FROM 
  deliveries 
WHERE 
  delivery_date BETWEEN DATEADD(month, -12, GETDATE()) AND GETDATE() 
GROUP BY 
  delivery_destination 
) 
SELECT 
  delivery_destination, 
  delivery_count 
FROM 
  CTE 
ORDER BY 
  delivery_count DESC 
OFFSET 0 ROWS FETCH NEXT 5 ROWS ONLY; 

2. Write a view to retrieve the total number of deliveries for each delivery destination for the past 6 months, grouped by destination state and city.

CREATE VIEW vw_delivery_destination_summary AS 
SELECT 
  dd.state, 
  dd.city, 
  COUNT(d.delivery_id) AS delivery_count 
FROM 
  deliveries d 
  INNER JOIN delivery_destinations dd ON d.delivery_destination = dd.destination_id WHERE 
  d.delivery_date BETWEEN DATEADD(month, -6, GETDATE()) AND GETDATE() 
GROUP BY 
  dd.state, 
  dd.city; 

3. Write a view to retrieve the average delivery time for each delivery destination, including the destination name, city, state, and average delivery time in hours.

CREATE VIEW vw_average_delivery_time AS 
SELECT 
  dd.destination_name, 
  dd.city, 
  dd.state, AVG(DATEDIFF(hour, d.delivery_start_time, d.delivery_end_time)) AS avg_delivery_time_hours 
FROM 
  deliveries d 
  INNER JOIN delivery_destinations dd ON d.delivery_destination = dd.destination_id GROUP BY 
  dd.destination_name, 
  dd.city, 
  dd.state;

Most Commonly Asked Interview Question

Q: What is the difference between a View and a Stored Procedure?

A: A View is a virtual table that retrieves data from one or more tables, whereas a Stored Procedure is a precompiled set of SQL commands that can perform actions such as insert, update, and delete data in the database. A View can be used to simplify the way you access data stored in the database, while a Stored Procedure can be used to perform complex operations.

For example, in a previous project, I used a View to retrieve the sum of delivery weight for each delivery destination in the transportation industry. This View was then used in multiple reports to display the delivery summary. On the same project, I also used a Stored Procedure to perform bulk updates to the delivery status based on certain criteria.

Conclusion

SQL Server Views are a powerful tool that can simplify the way you access data stored in the database. They can provide a consistent, controlled, and secure way of accessing the underlying data while abstracting the complexity of the underlying tables. In the transportation industry, SQL Server Views can be used to aggregate data, retrieve delivery details, and simplify the way you access data for reporting and analysis.

In conclusion, if you’re interested in a career in data analytics and you want to learn more about SQL Server Views, then book a call with our admissions team or visit training.colaberry.com to learn more.