ItalDesign Women's Boots Flat Chelsea Boots Grey nMTQKWnxLR

B0779G4H66
Ital-Design Women's Boots Flat Chelsea Boots Grey nMTQKWnxLR
  • Outer Material: Synthetic
  • Heel Height: 3 centimetres
  • Heel Type: Flat
  • Material Composition: synthetic
Ital-Design Women's Boots Flat Chelsea Boots Grey nMTQKWnxLR Ital-Design Women's Boots Flat Chelsea Boots Grey nMTQKWnxLR
back to main navigation
back to main navigation
back to main navigation
back to main navigation
back to main navigation

Thoughts on Java

You are here: / / 5 ways to initialize lazy associations and when to use them

By Fashion Thirsty Heelberry® Womens Ladies Block High Heels Ankle Strap Barely There Sandals Shoes New Size Red Faux Suede IF0G73gH
Think Womens 78707569 Boots Brown Nougat Brown 1V6hb

Lazy loading of associations between entities is a well established best practice in JPA. Its main goal is to retrieve only the requested entities from the database and load the related entities only if needed. That is a great approach if you only need the requested entities. But it creates additional work and can be the cause of performance problems if you also need some of the related entities.

Let’s have a look at the different ways to trigger the initialization and their specific advantages and disadvantages.

Don’t want to read? You can watch it here!

Lets start with the most obvious and unfortunately also the most inefficient approach. You use the find method on the EntityManager and call a method on the relation.

view raw mappedRelation.java hosted with by GitHub

Well, you probably know it. This code performs an additional query to initialize the relation. That doesn’t sound like a real problem, but let’s calculate the number of executed queries in a more real world-ish scenario. Let’s say you have an entity with 5 associations which you need to initialize. So you will get 1 + 5 = 6 queries .

OK, that are 5 additional queries. That still doesn’t seem like a huge issue. But our application will be used by more than one user in parallel (I hope).

Let’s say your system has to server 100 parallel users. Then you will get 100 + 5*100 = 600 queries . That is called the n+1 select issue, and it should be obvious that this is not a good approach. Sooner or later, the number of additionally performed queries will slow your application down. Therefore you should try to avoid this approach and have a look at some other options.

Join the Thoughts on Java Library

Get free access to:

Signup For Free:

Already a member? Login here.

A better option to initialize lazy associations is to use a JPQL query with a fetch join.

view raw fetchJoinJPQL.java hosted with by GitHub

The advantage is that Hibernate fetches everything within one query. From a performance point of view, this is much better than the first approach.

And the main disadvantage is that you need to write additional code which executes the query. But it gets even worse if the entity has multiple associations and you need to initialize different associations for different use cases. In this case, you need to write a query for every required combination of associations you want to initialize. That can become quite messy.

VogueZone009 Womens Soft Material Zipper Pointed Closed Toe HighHeels Solid Sandals Lightbrown BYaLjjrMt3
Sign In

The Genius of Flexibility Santa Barbara

We are centrally located downtown near Santa Barbara Street and Canon Perdido Street

888-730-7953 x3

Nike Men’s Magista Opus Ii Fg Football Boots Orange Laser Orange/Blackwhitevoltwhite SzKSR7t
Ariat Windermere Fur H2O Long Boot Free Postage Dark Brown HQQGdXJ8sK
Peeptoe Wedge Heel Suede of Patrizia Womens Dini Red RED nS9zEt
NVXIE Womens Ladies Boots Rough High Heel Square head Suede Pearl Lace Black Wine Red Fall Winter Party Work WINEREDEUR37UK455 nbhot3WjM5

The Genius of Flexibility Santa Barbara is housed in the greenest building in Santa Barbara , a Built Green environmentally retrofit 1920s era structure located in the historic Plaza de Alhecama in downtown Santa Barbara.

Located in the quiet park behind La Playa Azul Cafe and Zaytoon restaurant, our 100% solar powered facility is environmentally sensitive and energy efficient, featuring three open air and naturally lit rooms with radiant infrared heating throughout.

The Genius of Flexibility Santa Barbara center embodies our vision of an ideal work space: working inside a structure that is ecologically sound so as to reflect the sustainability we create within a person's body.

September 15-23, 2018 — Level I-III Certification Immersion

Crocs Swiftwater Men Clogs Blue Blue Jean/Slate Grey TaPXT9J9d

September 18-19, 2018 — Level II Certification

Webla Women Bowknot Slip on Casual Work Loafers Lazy Shoes Single Shoes Leisure Flats Blue 0RiAmNp

September 24-30, 2018 — Level V Certification

Daily classes avaiable with Bob Cooley, Elite Trainers, and Interns.

Our classes are appropriate for all ages, abilities, and backgrounds. They include lots of physical activity, but you work at your own pace. Learn the unique relationship between resistance, flexibility, and strength while also discovering concomitant physical, spiritual, emotional, and psychological benefits.

Beppi Sport Shoe 2155301 Women’s Fitness Black Preto jcxLuff

Private sessions avaiable with Bob Cooley, Elite Trainers, and Interns.

A private session is your appointment for intensive and personalized flexibility training. It starts with a one-on-one stretch program tailored to your body, your needs, and your goals.

Daily self-stretching, assisted stretching, and mashing private sessions, plus more.

Personal retreats are a great option for those who don't live near one of our centers but wish to experience all that Resistance Flexibility can offer. For both locals and visitors from around the globe, our personal retreats offer a comprehensive and concentrated training experience.

Learn

Connect

Caterpillar Womens White Colorado Curtsy Boots White/Pink w3rVR68Tk