Database Mail Architecture:

Database mail is newly introduced concept in SQL Server 2005 and it is replacement of SQLMail of SQL Server earlier version.
The main purpose of Database Mail is sending e-mail messages from the SQL Server Database Engine to users. We can send a text message, query result, failure alerts, file as attachment.
The database mail can be used to notify users or administrators regarding events raised in SQL Server.
To send Database Mail, you must be a member of the Sys admin <or >DatabaseMailUserRole database role in the msdb database.

How to configure the Linked Server

Step1.In SQL Server Management Studio, open Object Explorer, expand Server Objects, right-click Linked Servers, and then click New Linked Server.

Step2.In the new window on [General] page, we need to set several parameters as below:

How Linked Server Works

Linked Servers allows us to submit a TSQL statement on one SQL Server instance, which retrieves data[Table\View] from a different SQL Server instances.
In fact, linked server can be used to join data from multiple SQL Server instances using a single TSQL statement.
When you have databases on multiple SQL Server instances, you might find it useful to use linked servers in your application to retrieve data from more than one instance.
By using a linked server your application will only need to connect to one SQL Server instance to retrieve data from multiple SQL Server instances.
On that single SQL Server instance, we would define linked servers so your application could retrieve data from the databases that reside on a different SQL Server instance.

Cross Database Ownership Chaining

Cross Database Ownership Chaining is a mechanism of Microsoft SQL Server to grant a database 'A' user access to objects in databases B where he doesn’t explicitly got access-permissions to.
Note: By default Cross-database ownership chaining is turned ON for the master, temp db, and msdb system databases. You cannot change cross-database ownership chaining for the master, msdb, model, and tempdb system databases.
 By default you’re already using Cross Database Ownership Chaining on all of your SQL Servers. You surely already used a function or table of the master\temp-database. If you take a look at the security-configuration of the master-\temp database you will see that you’re mostly not explicitly granted access. That’s because Cross Database Ownership Chaining is applied in this operation.

SQL Server Architecture

How does the transaction log record a transaction\ How does the data file records a transaction.\How SQL query goes through.

Following is the process which a SQL Query goes through.