Menu
I'm writing an application that sync's entities from a third party datasource into our own schema, with a transformation/mapping step in between. I'm using Hibernate to represent and persist the entities in our own schema. A problem I'm running into is that I have a unique multi-column key on one of my tables. The behavior I would like to see is analogous to an upsert: when Hibernate goes to persist an entity and detects a unique constraint violation, it does an update instead. We are using MySQL, which provides an INSERT ... ON DUPLICATE KEY UPDATE syntax, but I'm not sure how or if Hibernate can be made to make use of it?
I suppose I could always try the insert, and if I catch an exception do an update, but that seems hacky and suboptimal. Any tips on a clean way to do this?
671
When you use . saveOrUpdate() Hibernate will check if the object is transient (it has no identifier property) and if so it will make it persistent by generating it the identifier and assigning it to session. If the object has an identifier already it will perform .
1. Overview. In this tutorial, we'll learn how we can batch insert and update entities using Hibernate/JPA. Batching allows us to send a group of SQL statements to the database in a single network call. This way, we can optimize the network and memory usage of our application.
Hibernate merge can be used to update existing values, however this method create a copy from the passed entity object and return it. The returned object is part of persistent context and tracked for any changes, passed object is not tracked. This is the major difference with merge() from all other methods.
1)First difference between save and persist is their return type. Similar to save method, persist also INSERT records into database but return type of persist is void while return type of save is Serializable object .
We are using MySQL, which provides an INSERT ... ON DUPLICATE KEY UPDATE syntax, but I'm not sure how or if Hibernate can be made to make use of it?
It looks like someone did it by overriding the sql-insert statement used by Hibernate for this entity. If you don't mind not being portable (and probably using a stored procedure), have a look.
I suppose I could always try the insert, and if I catch an exception do an update, but that seems hacky and suboptimal. Any tips on a clean way to do this?
Another option would be to:
But unless you lock the whole table(s) during the process, you can face some race condition in a multi-threaded and distributed environment and step #3 can potentially fail. Imagine two concurrent threads:
Thread 1:
Thread 2:
So you would have to implement some kind of retry mechanism anyway (locking the whole table(s) is not a good option IMO).
150
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
