Taking backup of data is important for one and all because you never know when your hard drive crashes and all of your data on it just wiped off or by mistake you deleted some important files. Few years back when online backup solutions were not available people used to backup their important data in the external disks but these solutions used to have their own limitations like portability issue , if you want to make your data available with you every time, you need to carry your disk with you every time that is not possible always , other drawback is that these disks are of limited size and as soon as your backup data size increases you need to buy more and more disks that will also introduce a burden of affordability whether you can afford it or not. Continue reading
Nobody would have ever imagined that a very small bug in the OpenSSL now famously known as Heartbleed could bring entire internet industry on its knees. Finally everything settled down without any major incident reported but steps need to be taken so that these types of bug can be avoided in future. You might find it surprising that OpenSSL project has only 1 full-time developer (Hats off to this guy) who is responsible for development and maintenance of OpenSSL libraries, mentioned by OpenSSL Software foundation president Steve Marquess in a blog post. Continue reading
This post is in continuation of our Update MongoDB Java Example series.
In the previous post we have seen some of the Atomic update modifiers provided by MongoDB with the help of a Java example ,that can be used to
update and add new key to a
document. Now we will move one step ahead and will look into the Array modifiers available in MongoDB. Below are the following Array Modifiers that we are going to cover in this post.
In the previous post i.e Document
Replacement in MongoDB we have
seen how we were updating the
document – first by getting the
document using findOne() , then
updating its values and finally
putting it back in the collection.
We can also achieve the same task
in a single step i.e skipping findOne() invocation and by using atomic update modifiers provided by mongodb. This post will focus on update mongodb java example. Continue reading
In the previous posts we have seen examples
on how we can query a MongoDB using Java. We have seen different ways in which we can invoke find() method and how to do comparison querying and logical querying. This post will focus
on updating of our existing documents present in our mongo database using Java.
Update MongoDB Java Example :
Here also, we will continue with the same example that we have used in our previous posts. Continue reading
I am sure that by this time all of us have already heard about the Heartbleed ,that made almost every encrypted sensitive data i.e passwords,credit card details etc vulnerable to external attacks.
These days almost each and every website asks user for registration and provides them with an username and password for there future interaction with the website.Today HTTPS protocol is the defacto standard for sending the sensitive data to the server and behind the scenes Secure Sockets Layer (SSL) and Transport Layer Security(TLS) protocols which make sure that every transaction between the client and server is secure. Continue reading
This post will focus on the logical
operators that are available in
momgodb.I will use Java for the
illustration purpose of these
operators. You can use any of
the language for which mongo
driver is available. For the comparison operators you can refer the previous post here.
There are 4 logical operators that have been documented in mongodb specs.
We will continue with the same example that we have seen in the previous post. Continue reading
In the previous post we have seen
different variations of find() method ,
but in real life we need much more than the exact matching e.g we want to query in ranges (using in ) , combine multiple conditions together (using OR , AND) , using negation etc. In this post we will cover the comparison query operators that comes under the conditional querying in MongoDB :
Here, we will continue with the same example that we have used in the previous post , in Continue reading
What is PermGen?
The permanent Generation is part of your heap space that is actually used to store meta-data information for the classes created by users and prior to Java 7, it is also used to store interned Strings (interned strings – used to remove String duplicates by internalizing them to reduce memory consumption). As of Java 7, intern strings also moved as a part of heap space to make the more space available in Continue reading
In the earlier post Mongodb java Hello World Example we have seen some basic operations on the MongoDB and searching the document was one of them there we had used find().In this post we will more focus on querying mongdb with java using find() method that is basically used for querying documents in mongodb collections. We will see that how we can use find() in different ways to meet our query needs.Below are the 4 basic scenarios that we are going to cover under querying mongodb java example.
- Fetching all the documents from a collection.
- Fetching a subset of documents from a collection.
- Fetching only selected keys of a document from a collection.
- Exclude some keys of a document from a collection.
For this example the document that we are using will have structure something like this , it has Continue reading