Remember, these are implicit methods provided by Spring Mongo Repository and hence no need to provide the definition in our EmplyeeRepository class. With just above definition, we can use below methods directly from our service class to perform queries on an Employee object. The insert method inserts a given new entity and returns the inserted entity. But, we mostly use save method for insertion and update both.
In this case, if an Id is already present in the given document then the document is updated else a new document is created. As you can see the findAll Sort sort method in the above definitions that returns a list of sorted document. This is a very useful method as the sorting becomes configurable in the server side with this implementation and we don't have to introduce multiple variables to keep a record of no of a total count of documents, no of pages, etc with the methods - getTotalPages , getTotalElements.
This method requires an instance of Sort class and there are 3 different methods to get an instance of it. We can use findAll Example empExample method by providing an example object to the method.
An Example takes a data object and a specification how to match properties. Below is an example:. All the examples above are the default and implicit methods that we get while using spring data mongo repository. To use any of the example above, you do not have to define any methods in the repository class. Now, let us see how we can define methods in the repository class to execute our custom queries to query MongoDB by our document attributes.
Above method finds employee by employee name and band and returns ordered result by salary. There are lots of keywords that are supported here. A complete list of supported keywords for query methods can be found on the official website. With this annotation, you can execute all the complex queries and it is also sometimes very useful to execute native MongoDB queries.
We have all the freedom to take advantage of MongoDB native operators and operations. The placeholder? By default, all the properties of Employee document will be fetched.
Now, if you want to ignore some of the properties in the result, you can use filter option. Here, the description attribute will be ignored. Let us see how we can use MongoDB specific operator using Query annotation. Below is an example of AND operator. Suppose you have an embedded collection. Let us say Department and Employee collections where each department can have multiple employees like our last article on spring boot MongoDB.
In this case, we require to execute some nested queries. Below query returns department collection whose employee's name is empName and salary greater then salary. Find centralized, trusted content and collaborate around the technologies you use most. Connect and share knowledge within a single location that is structured and easy to search. One other thing that puzzles me with this other finder is that it shows a limit 2 clause even though it is supposed to return only one Admin object.
I thought there would always be a limit 1 when returning one domain object. Is this a wrong assumption on Spring Data? When pasting in a MySQL client, the sql statements displayed in the console log, the logic works fine:. The EntityManager doesn't flush change automatically by default. You should use the following option with your statement of query:. When creating an integration test on a statement saving an object, it is recommended to flush the entity manager so as to avoid any false negative, that is, to avoid a test running fine but whose operation would fail when run in production.
Indeed, the test may run fine simply because the first level cache is not flushed and no writing hits the database.
To avoid this false negative integration test use an explicit flush in the test body. Note that the production code should never need to use any explicit flush as it is the role of the ORM to decide when to flush.
When creating an integration test on an update statement, it may be necessary to clear the entity manager so as to reload the first level cache. Indeed, an update statement completely bypasses the first level cache and writes directly to the database. The first level cache is then out of sync and reflects the old value of the updated object. To avoid this stale state of the object, use an explicit clear in the test body. Note that the production code should never need to use any explicit clear as it is the role of the ORM to decide when to clear.
Let's assume that we have a simple entity called Todo which source code looks as follows:. Our repository interface has a single method called updateTitle which updates the title of a todo entry. The source code of the TodoRepository interface looks as follows:.
The updateTitle method is not annotated with the Transactional annotation because I think that it is best to use a service layer as a transaction boundary. It has three components which are relevant to this problem:. The name of the DbUnit dataset file which is used to initialize the database to known state is toDoData. The name of the DbUnit dataset which is used to verify that the title of the todo entry is updated is called toDoData-update.
Any ideas why? The source code of the actual integration test looks as follows Remember to annotate the test method with the Transactional annotation :. After I run the integration test, the test passes and the title of the todo entry is updated.
The only problem which I am having is that the version field is not updated. I undestand that this description is a bit vague. If you want to get more information about writing integration tests for Spring Data JPA repositories, you can read my blog post about it.
I struggled with the same problem where I was trying to execute an update query like the same as you did-. This will work if you have put EnableTransactionManagement annotation on the main class. Spring 3. The underlying problem here is the 1st level cache of JPA. From the JPA spec Version 2. An EntityManager instance is associated with a persistence context.
A persistence context is a set of entity instances in which for any persistent entity identity there is a unique entity instance. This is important because JPA tracks changes to that entity in order to flush them to the database.
As a side effect it also means within a single persistence context an entity gets only loaded once. This why reloading the changed entity doesn't have any effect. Evict the entity from the EntityManager. This may be done by calling EntityManager.
Make sure changes to these entities get flushed first or you might end up loosing changes. Use EntityManager. Use a different persistence context to load the entity. The easiest way to do this is to do it in a separate transaction. One may wonder why the EntityManager is not just cleared after executing the query to avoid this inconsistency, but the reason for this is that there might be changes that have not yet been flushed, that would then be lost.
However, you do get the option of configuring this by setting the clearAutomatically attribute of the Modifying annotation to true. This ensures that the EntityManager is automatically cleared when the query has executed, ensuring that no entities are unsynchronized. This may be desirable in some situations, but it depends on the context in which the repository method is used, and thus you must be careful with this; it is easy to use such a method without noticing or remembering this side effect, and this could cause problems in your application.
Hopefully unit tests would be in place to catch mistakes like this, but it may not be the case. So use this flag wisely. Hi, I am calling a service where a user is created and the record created is later updated with a unique id. Im using Query for this. At the end of the service call I can see the data inserted into the table, However my update is not taking effect for uniqid. Any help on this? They are not the table name and column name.
As well I had to add Transactional to the method. Last, I had to create SessionFactory because I had another exception to specify the dialect and the annotated class.
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