Grunland Daie PA0464 Red Slippers Cloth Slippers Lady Multicolore 6MO2ROHmP

Grunland Daie PA0464 Red Slippers Cloth Slippers Lady Multicolore 6MO2ROHmP
  • Sole: rubber
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 Ladies Super Soft Real Leather Ultra Lightweight Comfort Mary Jane Espadrilles Sneakers Summer Shoes Size 38 Blue HJ0j2Q18q

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.

Palladium Unisex Adults Pampa Mono Chrome Mixte HiTop Trainers Gray 10 Black Black 315 RHCNsypYj hosted with by Nike Men’s Air Jordan 1 Mid Basketball Shoes Off White White/Pure Platinum/White AqDY02a5y

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 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.

Contact Us Angkorly Womens Fashion Shoes Sandals Pump Court Shoes Stiletto Multi Straps Stiletto High Heel 10 cm Black T4KaC

The Genius of Flexibility Santa Barbara

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

888-730-7953 x3

Carolbar Womens Chic Stylish Rivets Mid Heel Buckle Zip Short Boots Black FTcP15hx
Nearby Accommodations
TAOFFEN Women Fashion Cone Heel Slip On High Heel Court Shoes Office Shoes Black oYQ7kr6pN
Class Schedule

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.

Sandals ZHIRONG Womens Summer High Heel Vintage Rome Hollow Cross Straps Open Toe Thick Heel Shoes 75CM Color Beige Size EU38/UK55/CN38 Black vTB1ddcUJn

September 15-16, 2018 — Level I Certification

September 18-19, 2018 — Level II Certification

Best 4U Womens Sandals Summer Glitter Sequin Peep toe 14CM High Heels 3CM Platforms Rubber Sole One Buckle Pumps WjM4Qt4S

Womens sandals flip flops Kenya original Star red model with handmade beads unique pieces nr1ulvS

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.

Learn more

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.

Moonwalker Womens Genuine Leather Lace Up Military Ankle Boot Black Fur Lining HJ2ZRfq9

Onlineshoe Womens Ladies Ankle Strap Pastels Pointed Toe Low Mid Heel Mint Green Fuchsia Pink Black Coral Nude White Black Suede vFepXq

Pest species