#Database

Create an SQL query to identify customers registered with Gmail addresses from the 'users' database.

Write an SQL query to extract the third transaction of every user, displaying user ID, spend, and transaction date.

Design a database table structure ensuring proper normalization. Explain your thought process and the reasons for your design choices.

Explain the ACID properties in database transactions. Include examples to illustrate each property.

Describe what composite indexing is in databases. Provide examples of how and when it should be used effectively.