Evaluating Performance of Hibernate ORM based Applications using HQL Query Optimization

With the continuous advancement in technology, web technologies have reached to a new height. Enterprise applications are meant to be the basic need of today’s world which aims to produce results that are highly reliable, portable and adaptable. With these enormous features, they needed the storage mechanism which could handle and store the data effectively. The storage system thus required was a database management system but again technical knowledge was required to make things work appropriately. However, this approach was the traditional one which requires data to be stored in tabular format whereas Object oriented architecture has taken the programming language to a whole new technical phase for which the traditional RDBMS will not efficiently accomplish the expected job. To fulfill this gap in the literature, Object Relational Mapping is emerged as a solution to provide which provide comparative technical features effortlessly. These characteristics simplify and make the mapping of objects in object-oriented programming languages more flexible, efficient and easy to use. Therefore, we propose in this paper that Object relational Modeling (ORM) relates each object of object oriented languages to corresponding rows in the table. Oriental Journal of computer Science and technology Journal Website: www.computerscijournal.org ISSN: 0974-6471, Vol. 11, No. (2) 2018, Pg. 115-125

introduction On the temporary basis, filing and spreadsheets is used for storing massive data.However, commonly relational databases are used for the application and its availability.Relational databases require data to be stored in form of tables which is not sufficient.It does not work out with this fast emerging technical world and its needs.Since, now the time has gone where procedural languages were used.Today is an era of Object oriented programming which considers each and everything as an object and serves better for providing enterprise solutions.
The selection for Java language is justified since it is an open source language and also provides number of facilities such as: an API for querying and manipulating databases commonly termed as Java Database Connectivity (JDBC) API.Along with that, it gives the important transformation of information between the two sorts (JAVA and RDBMS) 1 .Also, there are number of ORM instruments to play out the activity by coding.

Literature Review
In modern development, Object Relational Mapping such as Hibernate has proved to be a good choice.Due to its portable and easy to use nature, it has been popular 2 .Different languages are pooled in a database application for data processing.They proposed a framework to optimized database applications which proves to be a significant solution in real world applications 15 .Various factors such as database access and efficiency influence Information management systems.A real case is enlightened to define hibernate ORM mechanisms 16 .ORM tools are used to map objects to and from relational form.This paper highlights the evaluation performance of open source object persistence 17 .
Our proposed study examines the ORM tool by performing distinctive tests, in various situations, this examination is centered on a wide assortment of hibernate consideration.Execution time is the basic measurement tool for it.

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It considers numerous situations especially related about one-to-many relation in hibernate.

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Correlates object database and ORM tools.

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Examines an ORM tool hibernates by performing distinctive investigations, in various situations.

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Has pleasantly centered on execution improvements.

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Drives attention on number of inquiries executed however following are also significant performance concerns.

ORM v/s Versant Object dB
Versant has more than 50000 users from different fields, like government, medical and telecommunication.
However, hibernate is a standard tool, used for ORM queries.It can be used with a relational database as well as with Oracle Enterprise edition.The comparison between features is shown in table 1.
The main concept behind the speed of hibernate is that the query is carried out on indexed columns of objects which ultimately makes hibernate much faster than versant so it has won this race in terms of performance.Both tools provide java interfaces, sessional control mechanism.Hibernate offers XML support in all cases but versant supports for some cases.

Hibernate v/s JPOX
This study examines the functioning of Hibernate and OpenJPA and JPOX and Speedo.
Diverse sort of tests were carried out that were greatly based upon and data retrieval.The following queries were utilized for execution tests.

• To l o a d o n e o b j e c t t w i c e w i t h i n a
transaction.

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To load a single object two time among these transactions.

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Lazy loading an object data.

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Eager loading an object data.
• Loading and saving similar and complex objects.
Processing time gives the immediate execution consequences and shows performance of ORM or persistence device for a particular test 5 .
The consequences of the lazy loading were better in the case of the Hibernate and OpenJPA than the JPOX and Speedo.
If the second query is concerned, ORM apparatus performed exceptional.The high hand of caching systems was proved to take place in this regard 3 .
So finally, it is concluded that hibernate played out the best general in majority of queries however, JDO marked its way in case of eager loading and complex objects.

Hibernating
Hibernate ORM (Object Relational Model) is a mediator between Java based objects and relational database which shapes the entities into object oriented domain.Hibernation enables malleable access to relational databases with high level object based functions.
The Figure 1 shows the layered architecture of Hibernate, which is used to help the users without knowing APIs.Hibernate uses database and configuration data to deliver services to the applications.

HQL clauses
Keywords such as SELECT, FROM and WHERE and so forth are utilized as Keyword for writing clauses to perform HQL operations.

fROM clause
Persistent objects are loaded using the From Clause into the memory.It requires Package and Class names.

AS clause
In the HQL queries, AS clause is utilized to allocate Aliases to the classes.This clause proves to be useful to manage long queries.The Aliases can be relegated to the classes specifically.

SELEct clause
The select condition empowers the designer to recover specific properties of the items instead of the entire question itself.The Select condition empowers the engineers to apply more control over the choice contrasted with the FROM statement 13 .

WHERE clause
Where provision empowers the engineer to characterize a condition in view of which the properties ought to be recovered, consequently empowering to limit the outcome.

ORdER BY clause
This statement is used to select the outcomes which arerecovered by the inquiry.The requesting/ arranging of the outcomes relies upon the boundary gave by the engineer which can either be DESC for descending order or ASC for ascending order.

uPdAtE clause
Engineers may utilize the Update Clause to refresh the properties of an object, the e.With the Hibernate 3, mass updates can be performed.With a specific end goal to execute the update, the execute Update() method is utilized 6 .

dELEtE clause
Delete clause is utilized by the designer to erase at least one object.The erasure of objects works contrastingly by comparing Hibernate 2 and 3.The execute Update() method is utilized for deleting purpose,.

inSERt clause
This clause is utilized to embed new records in HQL.

Object Relational Mapping (ORM)
Object Relational Mapping is a strategy that is utilized to bring similarity between the distinctive sorts of information.If an object is stored into data store and converted back to object without changing its properties, it is said to be persistent 8,14 .
One of the Code bits for this is:-A case of Office and Employee class is taken as an example.
The above mentioned code in figure 2  keys automatically the @id and @Generated Value is utilized they are also used to represent the primary key.@OneToOne comment gives affiliation the Employee class instances i.e. worker and manager.
Additionally the Employee class gives the data to create the employee instance.The code bit in Figure 3 displays how to make object relational mapping between a relational database and a programming dialect like JAVA.

Problems of data navigation
Java and relational databases both deal differently in getting to information and navigating or exploring from one object to next 11 .The associations can be either unidirectional or bidirectional.Java accesses data by making use of getter methods, e.g., getName().However, getting to a particular data in a relational database will require SQL queries which can be complicated much if it requires joins.
The performance can only be enhanced if minimum requests are made to database 9 .
inheritance Mapping Mapping of inheritance particularly defined at the object level is the real essence of inheritance mapping.To map a database scheme, three various inheritance techniques are listed out: Inheritance Mapping to Single Table : Nulls' Style A class with its entire subclasses is mapped to a single database table which can possible nullify few attributes in that table.That's the reason this type of mapping is referred to as Nulls' style.

inheritance Mapping to Multiple Style: ER Style
This technique plots a segment to no of tables in the database of the inheritance hierarchy.

Association Mapping
Association is the basic relation or affiliation between the two classes or the collection between the classes.
Three kinds of association mappings are defined below:

Experiment 1 Objective
Fetching Parameter Eager Using Hql Query Option

Result
As the outcome table displays, the normal queries count are ZERO.But, but it is not real scenario on account of the Fetch type utilized is Eager, as specified above.Which bring about stacking of total objects, in addition to the index and the different gathering of objects?conclusion There are different techniques for managing transactions implemented by systems that can affect system performances.This research basically focuses on how each system performs when recovering data, that's all important to focus on factors such as cache management, query language, and ORM functions that have these tools.Similarly, we used different types of searches to check the operation of different systems run.These queries are selected according to different criteria and navigation paths.These questions provide a way to check the different functions of systems, such as their search languages inheritance strategies and their caching mechanisms.These functions can help us decide which The system works better and what needs to be done to improve performance.It is very much clear from the results that utilizing Criteria API rather than conventional HQL Query will furnish result sets with wanted throughput that will upgrade the execution of querying.Moreover, recovering records utilizing LAZY fetch type will give low overhead to applications.A good ORM will automatically generate all the SQL needed to store the objects.
fig. 2 (a) Office and Employee class code

1: Structure of hibernating HQL
(Hibernate Query Language) and SQL (Structured Query Language) are almost similar.HQL, however, deals with objects and SQL works on tables.To carry out the interactions with relational databases, Hibernate transforms HQL queries into SQL.Not only this, Hibernate is itself capable of executive direct SQL queries.HQL is much preferred in order to avoid database portability issues which can arise in near future