Is NoSQL suitable for Selling Tickets Web Application?

I w开发者_StackOverflow中文版ant to write a high scalable web application for selling event tickets. I want to use NoSQL database, like Big Table or MongoDB and Cloud Service like Google App Engine (GAE) or Amazon Elastic Compute Cloud (Amazon EC2)

Is it posible using this type of database to be sure that two client will not be able to buy a ticket for the same place simultaneously? Or may be I will have to use RDBMS database and forget about Google App Engine?

Things like GAE's datastore can still support transactional semantics, for example:

http://code.google.com/appengine/docs/python/datastore/transactions.html

So yes, it is possible to do what you're seeking to do. (Note - GAE's Datastore is not exactly NoSQL, since it uses SQL-like queries.)

I have a problem with this question. Not all NoSQL databases are created equally, and different NoSQL databases have different ways they store data. Generally the thing you should be worried about are: data is actually written to disk and not just into memory. Most NoSQL databases can do this but not by default. Let's just say this is not a problem, you can usually tell the database like MOngo or Cassandra to write data to disk, can even tell how many servers at minimum the data should be written to.

The problem is that you may not get a true transactional support. When you deal with ecommerce it's important to have all or nothing type of transation where several operations either succeed completely or rolled back. There must be absolutely no chance that only part of your data is saved. For example, if you need to write data to more than one table (collection or document in NoSQL lingo), if server goes down in the middle of the process and your data is only written to one table, that's usually unacceptable in ecommerce.

I am not familiar with all NoSQL databases, but the ones I know don't have this option yet. MySQL, on the other hand, does.

If transactional support or lack of it does not bother you, then I think its OK to use NoSQL as long as you tell it to save data to disk and not just into memory.

The answer is 'maybe.'

Depending on what you're trying to build, you many be able to use some of the techniques in this post: http://kylebanker.com/blog/2010/06/07/mongodb-inventory-transactions/

Using something like get_or_insert you can easily ensure that two clients are not receiving the same resource simultaneously on Google App Engine. However, there are big differences between GAE and a RDBMS, so make sure you study them further before you make a decision.