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Database objects form the backbone of any database system, including Microsoft Azure. These objects help organize and manage data effectively. In this article, we will discuss some common database objects related to the Microsoft Azure Data Fundamentals exam. Let’s dive in!
Tables are fundamental database objects that store structured data. They consist of rows and columns, similar to spreadsheets. In Azure, you can create tables using SQL languages like Transact-SQL or NoSQL databases like Azure Cosmos DB.
Example:
CREATE TABLE Customers (
CustomerID int PRIMARY KEY,
CustomerName varchar(255),
ContactNumber varchar(15),
Email varchar(255)
);
Views are virtual tables that display a subset of data from one or multiple tables. They are defined by queries and don’t store any actual data. Views provide a way to simplify complex queries and control access to data by defining specific columns visible to different users or roles.
Example:
CREATE VIEW ActiveCustomers AS
SELECT CustomerID, CustomerName, ContactNumber
FROM Customers
WHERE IsActive = 1;
Indexes help improve the performance of queries by providing quick access to data. They are created on one or more columns of a table and are used to speed up searching, sorting, and filtering operations. Azure supports various types of indexes, including clustered, non-clustered, and full-text indexes.
Example:
CREATE INDEX IX_Customers_City ON Customers (City);
Stored Procedures are pre-compiled sets of SQL statements stored in the database. They allow you to encapsulate complex logic and execute it repeatedly. Stored procedures enhance security and performance by reducing network round trips. Azure offers support for stored procedures in various Azure database services like Azure SQL Database.
Example:
CREATE PROCEDURE GetCustomerByID
@CustomerID int
AS
BEGIN
SELECT * FROM Customers WHERE CustomerID = @CustomerID;
END;
Functions are similar to stored procedures but return values instead of executing a set of statements. They are often used to encapsulate reusable calculations or data transformations. Azure provides different types of functions, including scalar functions, table-valued functions, and system functions.
Example:
CREATE FUNCTION CalculateTotalPrice
(@UnitPrice decimal(18,2), @Quantity int)
RETURNS decimal(18,2)
AS
BEGIN
RETURN @UnitPrice * @Quantity;
END;
Triggers are special types of stored procedures that automatically execute in response to specific events on tables, such as insert, update, or delete operations. They are useful for enforcing business rules, data validation, and maintaining data integrity.
Example:
CREATE TRIGGER PreventDuplicateEmail
ON Customers
AFTER INSERT, UPDATE
AS
IF EXISTS (SELECT * FROM inserted i
INNER JOIN Customers c ON i.Email = c.Email
WHERE i.CustomerID <> c.CustomerID)
BEGIN
RAISERROR ('Email already exists!', 16, 1);
ROLLBACK TRANSACTION;
END;
These are just a few common database objects related to the Microsoft Azure Data Fundamentals exam. Understanding these objects and their usage is essential for successfully working with Azure database services. Happy learning!
Correct answer: c. Blob container
Correct answer: c. Azure SQL Database
Correct answer: True
Correct answer: b. Document
Correct answer: d. Azure Cosmos DB
Correct answer: True
Correct answer: d. Directory
Correct answer: a. Azure Storage
Correct answer: True
Correct answer: d. Entity
33 Replies to “Identify common database objects”
Much appreciated!
Great post! Understanding database objects is crucial for passing the DP-900 exam.
Thanks for the insightful article!
Very informative post.
This was an excellent primer on database objects.
The index section was a bit confusing.
Try looking at some examples of queries with and without indexes. It helps to visualize how they work.
Can anyone break down foreign keys for me?
Foreign keys are used to link two tables together. They enforce referential integrity by ensuring that a key value exists in the related table.
Good point. They prevent orphan records, which are essentially rows that reference non-existent entries in other tables.
What about triggers? Are they important?
Triggers are automatic actions that occur when certain conditions are met. They can be used for logging, enforcing business rules, and more. Definitely worth knowing.
Indeed, triggers can be very useful but also need to be used cautiously as they can complicate debugging.
Are there certain database objects we should prioritize for DP-900?
Focus on tables, views, indexes, and stored procedures. These are fundamental and often appear in exam questions.
Appreciate the breakdown on indexes.
Could have used more examples.
I found this very helpful. Can anyone explain the difference between tables and views?
Tables store the actual data in rows and columns. Views are virtual tables created by querying one or more tables. They don’t store data themselves.
Adding to that, views can help simplify complex queries by encapsulating them into simple queries.
Are CTEs (Common Table Expressions) covered in the DP-900 exam?
CTEs might come up. They are useful for simplifying complex joins and subqueries.
Kudos to the author, this is a well-written piece.
Nicely written! Helped a lot.
Views vs Materialized Views? Any thoughts?
Good point! Materialized views are great for read-heavy workloads where data doesn’t change often.
Materialized views store the result set on disk, making query retrieval faster, but they require refreshing. Regular views are always up-to-date but may be slower for complex queries.
Question: How do stored procedures compare to functions in SQL?
To add, functions can be used in SQL statements like SELECT, but stored procedures cannot.
Stored procedures can perform actions like modifying data, whereas functions are generally used for computations and must return a value. Stored procedures can also call functions.
How important is understanding indexes for the DP-900 exam?
It’s quite important. Indexes improve query performance, and knowing different types like clustered vs non-clustered can help you optimize your database.
Yes, and you should also know when not to use indexes, as they come with maintenance overhead.