Apr 15
An object by itself is intensely uninteresting.Objects contribute to the behavior of a system by collaborating with one another.One of relationship aspects between Objects can be represented by Association.
When we bring in Cardinality in Association we get One-to-One, One-to-Many and Many-to-Many.In later two One-to-Many and Many-to-Many we use Collection to represent many Side.For example: An Order have many OrderDetail’s.
We have these associations represented in Relational DBMS using foreign keys.So from any O-R framework we expect that to take care of these associations in smartest way possible.As these can easily become a performance bottle neck for the application.Some time you may end up loading lot of Data into memory, and sad part is you are never going to use them. Continue reading »
Mar 29
Here I will discuss each and every thing that is required to create a business application for iPhone. If you have tried any business application or if you have read the User Interface Guide on Apple’s developer site, you will agree that almost all the business applications invlolve atleast one UITableView. Also the UI is very neatly designed and does not involve any flashy UI elements.
So In next few posts I am going to create each of those elements required to make a successful business application and at the end I will be demostrating a sample application that downloads data from a server and displays the information in a neat way.
Following is the list of topics under this catogory:
Continue reading »
May 05
In this blog, I take a look at the query cache, well it is more than a cursory glance, would try to dive in some detail. The blog would explain some of the details of it (enough introduction, lets get to the meat).
As most of us already know, hibernate supports plugging in external cache providers for addressing certain aspects of performance. There are some very good articles on hibernate caching, some of which are
Understanding the second level and query cache
Chapter 19: Improving performance
Lets start with what we are trying to achieve by query cache. The intention is to cache the results against the query (the sql along with the parameters and their values). The effectiveness of the cache is determined to a large extent by its invalidation logic. The isolation level semantics that we want the cache to follow also impacts this logic. In this blog I will go over some of the these details and how it impacts some of the performance choices I need to make. Rather than detail the implementation logic, will run over some common scenarios explaining the implementation detail along the way. Continue reading »
Apr 07
Persistence in enterprise solutions is not only about CRUD operations, but handling concurrency. Concurrency is handled mostly by locks at the database levels. These locks are configured at the dataobject level and cannot be easily controlled from the flow. The only way of controlling it based on the flow is a programmatic approach to it (via JPA locking api or equivalents). Most of the concurrency issues are discovered only in the later stages of development or at times only after the application goes live, a code change at these points is very difficult. Continue reading »
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