You can enable anonymous, public read access to a container and its blobs in Azure Blob storage. By doing so, you can grant read-only access to these resources without sharing your account key, and without requiring a shared access signature (SAS).
Public read access is best for scenarios where you want certain blobs to always be available for anonymous read access.
Reference:
https://docs.microsoft.com/en-us/azure/storage/blobs/storage-manage-access-to-resources

Explanation

Box 1: DataFrame
DataFrames
Best choice in most situations.
Provides query optimization through Catalyst.
Whole-stage code generation.
Direct memory access.
Low garbage collection (GC) overhead.
Not as developer-friendly as DataSets, as there are no compile-time checks or domain object programming.
Box 2: parquet
The best format for performance is parquet with snappy compression, which is the default in Spark 2.x.
Parquet stores data in columnar format, and is highly optimized in Spark.

Explanation

DB1: Transparent Data Encryption
Azure SQL Database currently supports encryption at rest for Microsoft-managed service side and client-side encryption scenarios.
Support for server encryption is currently provided through the SQL feature called Transparent Data Encryption.
Columns: Always encrypted
Always Encrypted is a feature designed to protect sensitive data stored in Azure SQL Database or SQL Server databases. Always Encrypted allows clients to encrypt sensitive data inside client applications and never reveal the encryption keys to the database engine (SQL Database or SQL Server).
Note: Most data breaches involve the theft of critical data such as credit card numbers or personally identifiable information. Databases can be treasure troves of sensitive information. They can contain customers' personal data (like national identification numbers), confidential competitive information, and intellectual property. Lost or stolen data, especially customer data, can result in brand damage, competitive disadvantage, and serious fines--even lawsuits.
References:
https://docs.microsoft.com/en-us/azure/security/fundamentals/encryption-atrest
https://docs.microsoft.com/en-us/azure/security/fundamentals/database-security-overview

CONT_SQL3 with the SQL Server role, 100 GB database size, Hyper-VM to be migrated to Azure VM.
The storage should be configured to optimized storage for database OLTP workloads.
Azure SQL Database provides three basic in-memory based capabilities (built into the underlying database engine) that can contribute in a meaningful way to performance improvements:
In-Memory Online Transactional Processing (OLTP)
Clustered columnstore indexes intended primarily for Online Analytical Processing (OLAP) workloads Nonclustered columnstore indexes geared towards Hybrid Transactional/Analytical Processing (HTAP) workloads References:
https://www.databasejournal.com/features/mssql/overview-of-in-memory-technologies-of-azure-sqldatabase.html

References:
https://docs.microsoft.com/en-us/azure/security/fundamentals/encryption-atrest
https://docs.microsoft.com/en-us/azure/security/fundamentals/database-security-overview