How to Create SQL View: Step by Step Instructions
SQL is one of the core data management systems in the database wherein users can retrieve, manipulate, and manage data efficiently. The most important concepts that SQL have would be a view since it helps the user to simplify complex queries, enhances security, and gives organization in the presentation of the data. This article will explain what it is, why it is important, and how to create and manage views in SQL.
What is a SQL view?
A view is a virtual table based on the result-set of a SELECT statement. Unlike an ordinary table, a view does not store data in a physical place. Rather, data is retrieved dynamically from one or more tables whenever it is accessed.
A view in simple terms can be considered as a window to your database: it only lets you view the data you wish to see in a form you need, but not reveal the complexity behind it.
Use views in constraining user access by giving permission to certain views and not the whole table.
Data Abstraction
However, display data in a form appropriate to an application or to a user by suppressing columns or rows that don't relate.
Data Integrity
Views maintain integrity in that the same rule applies to many applications or users.
How To Create a View in SQL
1. Easy Syntax
This is the basic form of a CREATE VIEW statement:
CREATE VIEW view_name AS
SELECT column1, column2, .
FROM table_name
WHERE condition;
view_name: This is going to be the name you are assigning to your view.
SELECT query: Defines which information should be included in the view.
| 1 | Alice | HR | 60000 |
| 2 | Bob | IT | 80000 |
| 3 | Charlie | Finance | 70000 |
Create a view which returns only employees belonging to the IT department:
CREATE VIEW IT_Employees AS
SELECT employee_id, name, salary
FROM employees
WHERE department = 'IT';
Now, while running the IT_Employees view, you would get:
SELECT * FROM IT_Employees;
Output:
| employee_id | name | salary |
|-------------|------|---------|
| 2 | Bob | 80000 |
3. Creating Views with Joins
Views can also apply joins to combine data from more than one table.
Let's say we have another table departments:
| department_id | department_name |
|---------------|-----------------|
| 1 | HR |\\
| 2 | IT |
| 3 | Finance |
To create a view that will show the employees along with department names:
CREATE VIEW Employee_Department AS
SELECT e.employee_id, e.name, d.department_name
FROM employees e
JOIN departments d
ON e.department = d.department_name;
4. Views Update
The update of a view is done using CREATE OR REPLACE statement when it exists.
CREATE OR REPLACE VIEW IT_Employees AS
SELECT employee_id, name
FROM employees
WHERE department = 'IT';
End
5. Dropping Views
To delete a view from a database use the DROP VIEW statement as follows:
DROP VIEW IT_Employees;
End
Best Practices for Using Views
1. Use Descriptive Names
Ensure that view names are descriptive in nature, for example: Sales_Report_View.
2. Limit Columns and Rows
Do not bring unnecessary columns or rows to improve performance.
3. Simple Views
This keeps it simple enough not to make the logic too complicated in views.
Up-to-date Views
Views should always have the latest available schema and data requirements updated.
4. Up-to-date Views
Views should always have the latest available schema and data requirements updated.
Conclusion
SQL views are a great abstraction, a security tool, and simplification of operations with a database. You can be either a starter or an experienced developer and understand the very basics of views and do much more concerning database management. Along the way, some examples and best practices will be followed throughout the guide, and hopefully, with confidence, create and manage your views for your projects.
Ready to simplify your SQL queries with views? Try it out now!
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