database question for beginner

[c++thriller]

I am a beginner just picking up .NET and ASP. I am getting into a chapter of study on databases. Most books that combine ASP, .NET and databases give simple examples of data storage that could otherwise be stored in a simple Excel sheet or Access book. SQL makes it easy to store simple info like name, phone, address, etc.... But I am just curious, for websites that store more complex information like stock info and large binary files customized by a user, how are these data stored? Are they generally stored in SQL? Or are they indexed onto a file system? Suppose a site lets you upload youtube videos after you login. In such scenarios, what is the contemporary practical approach? To store the youtube binary in SQL or have an index to the file in SQL and have the binary youtube file indexed into a non-database filesystem?

[hspc]

As usual with this kind of decisions. It depends.
Generally, if you need complex joins and transactional store then an RDBMS like SQL Server is a good choice.
Other options for more flexible data structures can be document databases.
BLOBs like videos and other files are better stored outside the database. Although some popular CMSs like SharePoint store BLOBs in the DB by default and it uses MS SQL Server by the way.
This forum we're using uses MySQL which is another popular RDBMS.
So when making your decision about the data store, you need to take several consideration like:

• Are ACID properties required?
• How complex is data retrieval?
• Performance
• Availability
• Cost

I hope this helps a bit