Skip to main content

Hibernate - Why need Hibernate

The most common approach to Java persistence is for application programmers to work directly with SQL and JDBC. After all, developers are familiar with relational database management systems, they understand SQL, and they how how to work with tables and foreign keys. Moreover, they can always use the well-known and widely used data access object patttern to hide complex JDBC code and nonportable SQL from the business logic.  However, this work usually ends up consuming a large portion of the development effort. Furthermore, when requirements change, a hand-codes solution always requires more attention and maintenance effort.

A ORM implementation is a complex beast - less complex than an application server, but more complex than a web application framework like Struts. Why should we introduce another complex infrastructural element into our system?Will it be worth it?
A supposed advantage of ORM (object/relational mapping) is that it shields developers from messy SQL.

Now, let's look at some of the benefits of ORM and Hibernate:
Productivity: Persistence-related code can be perhaps the most tedious code in a Java application. Hibernate eliminates much of the grunt work and lets you concentrate on the business problem -No matter which application-development strategy you prefer - top-down, starting with a domain model, or bottom-up, starting with an existing database schema.

Maintainability: Fewer lines of code(LOC) make the system more understandable, because it emphasizes business logic rather than plumbing. In systems with hand-coded persistence, an inevitable tension exists between the relational representation and the object model implementing the domain. Changes to one always involve changes to the others. ORM provides a buffer between the two models, allowing more elegant use of object orientation on the Java side, and insulating each model from minor changes to the other.

Performance: The people who implemented your ORM software had much more time to investigate the performance optimizations than you have.

Vendor independence: An ORM abstracts your application away from the underlying SQL database and SQL dialect.


I really don't want to use SQL again and again even for very simple relationship project. Hibernate will help to mediate the application's interaction with a relational database, leaving the developer free to concentrate on the business problem at hand.

Labels:

Comments

Post a Comment

Popular posts from this blog

Quicksort implementation by using Java

 source: http://www.algolist.net/Algorithms/Sorting/Quicksort. The divide-and-conquer strategy is used in quicksort. Below the recursion step is described: 1st: Choose a pivot value. We take the value of the middle element as pivot value, but it can be any value(e.g. some people would like to pick the first element and do the exchange in the end) 2nd: Partition. Rearrange elements in such a way, that all elements which are lesser than the pivot go to the left part of the array and all elements greater than the pivot, go to the right part of the array. Values equal to the pivot can stay in any part of the array. Apply quicksort algorithm recursively to the left and the right parts - the previous pivot element excluded! Partition algorithm in detail: There are two indices i and j and at the very beginning of the partition algorithm i points to the first element in the array and j points to the last one. Then algorithm moves i forward, until an element with value greater or equal
Post a Comment
Read more

Live - solving the jasper report out of memory and high cpu usage problems

I still can not find the solution. So I summary all the things and tell my boss about it. If any one knows the solution, please let me know. Symptom: 1.        The JVM became Out of memory when creating big consumption report 2.        Those JRTemplateElement-instances is still there occupied even if I logged out the system Reason:         1. There is a large number of JRTemplateElement-instances cached in the memory 2.     The clearobjects() method in ReportThread class has not been triggered when logging out Action I tried:      About the Virtualizer: 1.     Replacing the JRSwapFileVirtualizer with JRFileVirtualizer 2.     Not use any FileVirtualizer for cache the report in the hard disk Result: The japserreport still creating the a large number of JRTemplateElement-instances in the memory        About the work around below,      I tried: item 3(in below work around list) – result: it helps to reduce  the size of the JRTemplateElement Object        
1 comment
Read more

Stretch a row if data overflows in jasper reports

It is very common that some columns of the report need to stretch to show all the content in that column. But  if you just specify the property " stretch with overflow' to that column(we called text field in jasper report world) , it will just stretch that column and won't change other columns, so the row could be ridiculous. Haven't find the solution from internet yet. So I just review the properties in iReport one by one and find two useful properties(the bold  highlighted in example below) which resolve the problems.   example: <band height="20" splitType="Stretch" > <textField isStretchWithOverflow="true" pattern="" isBlankWhenNull="true"> <reportElement stretchType="RelativeToTallestObject" mode="Opaque" x="192" y="0" width="183" height="20"/> <box leftPadding="2"> <pen lineWidth="0.25"/>
4 comments
Read more