Active Oldest Votes. Improve this answer. Bill Karwin Bill Karwin k 81 81 gold badges silver badges bronze badges. I know, that benchmarks are evil, but is it really not possible? This doesn't make queries run faster. But is it easier to learn how to use a complex ORM, or how to use transactions?
Bill Yes, of course query is a query and it won't run faster. But some may manage set of queries better or worse. Doctrine provides optimal way to deal with these common scenarios, which is a general performance benefit. Speed is not only about the speed of single query. PatrikAkerstrand PatrikAkerstrand Optimization of queries important consideration if doctrine make it auto and zend-db not make it auto. Thank you — Ben. Sign up or log in Sign up using Google. You can not rely on a generated identifier being not available after a failed flush operation.
Do not pass detached entities to the persist operation. By applying the remove operation on some entity, that entity becomes REMOVED, which means that its persistent state will be deleted once EntityManager flush is invoked. The entity will be deleted on the next invocation of EntityManager flush that involves that entity. This means that entities scheduled for removal can still be queried for and appear in query and collection results.
After an entity has been removed its in-memory state is the same as before the removal, except for generated identifiers. Removing an entity will also automatically delete any existing records in many-to-many join tables that link this entity. The action taken depends on the value of the joinColumn mapping attribute onDelete. Deleting an object with all its associated objects can be achieved in multiple ways with very different performance impacts. Calling remove on an entity will remove the object from the identity map and therefore detach it.
Querying the same entity again, for example via a lazy loaded relation, will return a new object. Changes made to the detached entity, if any including removal of the entity , will not be synchronized to the database after the entity has been detached. There are several situations in which an entity is detached automatically without invoking the detach method:. The detach operation is usually not as frequently needed and used as persist and remove.
Merging entities refers to the merging of usually detached entities into the context of an EntityManager so that they become managed again. The state of the passed entity will be merged into a managed copy of this entity and this copy will subsequently be returned.
The reason for this is, if you serialize a class that was a proxy instance before, the private variables won't be serialized and a PHP Notice is thrown. The merge operation will throw an OptimisticLockException if the entity being merged uses optimistic locking through a version field and the versions of the entity being merged and the managed copy don't match.
This usually means that the entity has been modified while being detached. The merge operation is usually not as frequently needed and used as persist and remove. The most common scenario for the merge operation is to reattach entities to an EntityManager that come from some cache and are therefore detached and you want to modify and persist such an entity.
If you need to perform multiple merges of entities that share certain subparts of their object-graphs and cascade merge, then you have to call EntityManager clear between the successive calls to EntityManager merge. Otherwise you might end up with multiple copies of the same object in the database, however with different ids. If you load some detached entities from a cache and you do not need to persist or delete them or otherwise make use of them without the need for persistence services there is no need to use merge.
The state of persistent entities is synchronized with the database on flush of an EntityManager which commits the underlying UnitOfWork.
The synchronization involves writing any updates to persistent entities and their relationships to the database.
Thereby bidirectional relationships are persisted based on the references held by the owning side of the relationship as explained in the Association Mapping chapter. When EntityManager flush is called, Doctrine inspects all managed, new and removed entities and will perform the following operations.
As soon as you begin to change the state of entities, call persist or remove the contents of the UnitOfWork and the database will drive out of sync. They can only be synchronized by calling EntityManager flush. This section describes the effects of database and UnitOfWork being out of sync. EntityManager flush is never called implicitly by Doctrine. You always have to trigger it manually. For all initialized relationships of the new or managed entity the following semantics apply to each associated entity X:.
The flush operation applies to a removed entity by deleting its persistent state from the database. And you'll still be writing the mapping info, just in another place. Personally, I'd go with annotations, since it's a lot easier to find examples and info if you need them. There is one disadvantage about using Annotations. Since they are defined on the comments which is weird , you will NOT be able to use precompilers like Zend Guard or some bytecode php caching extensions to enhance your code performance some of them strip the comments.
Because annotation is the only specification with this technical impairment, I would NOT recommend using it. Documentation examples for XML is the poorest amongst all the options. Result Cache In stead of using you own caching mechanisms, you could use Doctrine's result cache. Only authorized users can answer the question. Please sign in first, or register a free account. Not the answer you're looking for?
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