August 29, 2013

After renaming I can't access MongoDB collection! :(

Yesterday while I was doing some test for performance team, I renamed a collection. Actually I renamed system.profile into "Profiling_28-08-2013". Then I couldn't access it. I couldn't delete that collection use db.Profiling_28-08-2013.drop(). After renaming MongoDB shell can't access that object. 
1. JavaScript execution failed: ReferenceError: <Part of collection name> is not defined
 2. JavaScript execution failed: SyntaxError: Unexpected token ILLEGAL
 3. <Part of collection name> is not a legal ECMA-262 octal constant (shell):1
 4. SyntaxError: missing ; before statement (shell):1
 5. ReferenceError: <Part of collection name> is not defined (shell):1
Those errors I got by trying combination against MongoDB several versions. First two errors I got from  MongoDB 2.4 and the rest from MongoDB 2.2.

If you have "-" inside your new collection name without any numbers you will get first error. Rest errors you will only get if you have "-08" like parts in your collection names.

MongoDB version 2.4.3 Shell version 2.4.3
MongoDB version 2.2.3 Shell version 2.2.3

Now you may want to get rid from those collections or you may want precious data in those collection. You can use runCommand to rename those collections or to drop them.
db.runCommand({drop:"test.Profiling_28-08-2013"});
db.runCommand({drop:"test.post-old"});
Rename commands you may have to run against the admin database. For rename you may have to use complete namespace. But dropping you can do with just collection name. It is recommended to use namespace when you are dropping.
db.runCommand({ renameCollection: "test.Profiling_28-08-2013", to: "test.newCol"});
db.runCommand({ renameCollection: "test.post-old", to: "test.newCol"});

Data Science for Business

Thanks Foster and Tom for this great book! Since the trend in the industry is towards Big Data and Data Science, I was reading and learning about them. When I found this book, I felt like I found something valuable. And I couldn't wait until start reading this book. This book's introduction says that this book will not be too much technical. That was not a problem because this book's title itself gives a idea that this book is not for technical people. But I'm a technical guy. 

When we are explaining something to our managers, we have to be-careful. Because there is a possibility that  Manager will misunderstand what we are explaining. Such a scenario relevant Data Science, this book will help you for sure. Because this book tells you why you want Data Science and how you use it with business. Then you can use Data Science to gain market share or to increase revenues. If you are a manager, it will be helpful to read and understand your techies. If you are a techie, you should this book to explain how you would be useful to business.

I like this book although it is not too much technical. But that doesn't mean that this book doesn't include any kind of technical stuff. I like this book! Thumbs u
p!

You can buy this book from here

August 12, 2013

Training Kit (Exam 70-463): Implementing a Data Warehouse with Microsoft SQL Server 2012

It's time to learn about Data Warehousing. I was really interested about Data Science. But I really didn't had much idea about Enterprise reporting, or analysis. But this book give much more than Microsoft SQL Server BI tool (Business Intelligence). It helped me to learn basics, some of theories about Data Warehousing. Because I learned things from the scratch, I think this is good for beginners. But you have to have a little bit of SQL Server exposure before.

This is not just a exam prep. This is something more than that. You can learn for exam as well. If you love to start learning Data warehousing with SQL Server, you can go with this book. This book gives you a good start for sure. I love Microsoft Press exam training kits because they have nice questions and explained answers which you can measure yourself.

This book is available as ePub, Mobi, PDF. So you can think about purchasing ebook also.

You can buy this book from here : http://shop.oreilly.com/product/0790145345219.do