Interesting Findings in SQL Server

Interesting findings articles gives small tips and findings 

you can use for the particular technology

Difference between datetime and datetime2 (SO)

DATETIME2 has a date range of "0001 / 01 / 01" through "9999 / 12 / 31" while the DATETIME type only supports year 1753-9999

DATETIME2 is more accurate when compared to DATETIME

What is LocalDB
This was introduced in SQL Server 2012. It's basically a new version of SQL Server Express intended for developers so you don't need to install SQL Server. 
http://stackoverflow.com/a/18781150/340046
http://blogs.msdn.com/b/sqlexpress/archive/2011/07/12/introducing-localdb-a-better-sql-express.aspx

MDF File
It is SQL Server data file. 
http://stackoverflow.com/questions/1175882/what-is-an-mdf-file

SQL Server Service Broker
Provides native support for messaging and queuing application in SQL Server Database engine. Developers can use Service broker to distribute data workload across databases. (See MSDN article)

YouTube Results for SQL Server Service Broker

Delete options for Tables
You can specify what to do when you delete a row in a table.
CASCADE : Corresponding tables are updated
see column_constraints.
http://stackoverflow.com/questions/17976689/do-i-need-to-specify-on-delete-no-action-on-my-foreign-key
http://www.techonthenet.com/sql_server/foreign_keys/foreign_delete.php
http://stackoverflow.com/questions/59297/when-why-to-use-cascading-in-sql-server
http://stackoverflow.com/questions/278392/should-i-use-the-cascade-delete-rule
http://stackoverflow.com/questions/3656099/how-to-delete-rows-in-tables-that-contain-foreign-keys-to-other-tables
https://technet.microsoft.com/en-us/library/aa902684(v=sql.80).aspx

SQL Server Agent
Component of SQL server which schedules jobs and handles other tasks. SQL Server Agent runs as a windows service.