I have a situation where I am making a read request to a database with a long, complex query that needs to map to a complex object. Based on my research, it looks like I want to use #SqlResultSetMapping to handle the mapping, but I would like to put my query into the jpa-named-queries.properties file because it is so long. I can only find examples of #SqlResultSetMapping with #NamedNativeQuery that shows the query passed into the query parameter of the annotation as a string. Is it possible to use #SqlResultSetMapping with an externalized query, and if so, can anyone provide and example of how to do this? Thanks!
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I am trying to implement REST query param "fields" with Mapstruct. The REST "fields" query param by convention lets you specify as its value a comma separated list of the fields of the entity you want in the response when you are preforming a GET request on an entity. This is opposed to returning all the fields of entity, which is what happens when "fields" query parameter is omitted.
Example:
GET locahost/blah/1
Response {"a":"1", "b":"2", c:"3"}
GET local/blah/1?fields=a,c
Response {"a":"1", "c":"3"}
So what I want Mapstruct to do is only map the bean's fields who's fields' names I specify. Note I need to be able to specify the bean's fields' names I want to map at runtime. Why? The fields I wish to map change from call to call of the GET method.
From what I read in the MapStruct documentation, you can specify what fields to map or not map with annotations. Unfortunately you can't change the annotation value at runtime (It maybe possible through reflection, but it feels should be a better way).
Given what I want to do, does anyone know how I can specify at runtime what fields are mapped?
Or alternately does anyone know a better way of implementing the REST "fields" query param?
I Look forward to reading the responses. If you have any questions or need clarifications just ask 🙂.
Regards,
Ben.
Thinking about this, I think that it doesn't make sense. As MapStruct generates the mapper classes at build time and therefore can't changing the mapping process at runtime. Is this right?
Is there a way in hibernate-search 6 to project multiple fields and map them directly to a POJO object or I should handle it by myself. I'm not sure that I understand the composite method described in the documentation. For example I can do something like that:
SearchResult<List<?>> result = searchSession.search(indicies)
.select(f -> f.composite(f.field("field1"), f.field("field2"), f.field("field3"),f.field("field4")))
.where(SearchPredicateFactory::matchAll)
.fetch(20)
And then I can manually map the returned List of fields to a POJO. But is there a more fancy way to do that without the need to manually loop through the list of fields and set them to the POJO instance?
At the moment projecting to a POJO is only possible for fairly simple POJOs, with up to three fields, using the syntax shown in the documentation. For more fields than that, you have to go through a List.
If you're using the Elasticsearch backend, you can theoretically retrieve the document as a JsonObject and then use Gson to map it to a POJO.
There are plans to offer more fancy solutions, but we're not there yet.
Due to some odd reason, I cannot go with JPA vendor like Hibernate, etc and I must use MyBatis.
Is there any implementation where we can enrich similar facility of CRUD operation in Mybatis?
(Like GenericDAO save, persist, merge, etc)
I have managed to come up with single interface implementation of CRUD type of operations (like Generic DAO) but still each table has to write it's own query in XML file (as table name, column names are different).
Will that make sense to come up with generic implementation?
Where I can give any table object for any CRUD operation through only 4 XML queries. (insert, update, read, delete) passing arguments of table name, column names, column values..etc.
Does it look like re-inventing the wheel in MyBatis or does MyBatis has some similar support?
you can try Mybatis Plus.This is for these cases.
MyBatis is not an ORM, instead it maps the result from SQL statements to objects.
You need to write SQL.
You will have a hard time if you try and apply the JPA model to working in MyBatis. You need to learn how MyBatis works instead.
You may be interested in the MyBatis Generator. Here is a screenshot of the introduction paragraph.
And here is the URL.
The generator looks at the Physical tables in an RDBMS and generates the CRUD mapping.That is half the job done. The other half is to utilize these mappings in your actual code.
Let this assumption also be cleared. The generator generates only the CRUD. For more complex operations like aggregations or joins et al, you may need to write the mappers on your own.
Is there any way to retrieve the column metadata from a query (something like what DbDataReader.GetSchemaTable() does)? I'm basically looking for things like a columns length if it's a string, or if it's a numeric field its precision/scale. This info seems to be lost as it gets projected into a class.
I know you can query the static table metadata, but that doesn't really help me. I also know I can get the DbDataReader if I run an explicit SQL query instead of using LINQ. But I really don't want to do that in this case.
I've been digging through the EF 6 source code and it doesn't look like it exposes this metadata anywhere - but there is a lot going on so it's possible I missed it or didn't think of some way of getting to it.
Any ideas?
First post here so sorry if I seem like a newb,
I am trying to find a way to use Zend_Auth_Adapter with a data mapper, but seem to be struggling. I know I can use Zend_Auth_Adapter_DbTable and associate this with a db table, but this seems to negate the whole reason for having a data mapper (I think)?! Should I be creating a custom adapter for the mapper so that I can use the mapper to choose whatever I want as my data source?
Good question. The proper way to do that would be to roll your own Zend_Auth_Adapter. I have done so for Doctrine (my ORM).
I also use the data mapper pattern throughout my application, but I do not use it for my authentication. It adds a lot of needless overhead imo. I just query the database directly using my Auth_Adapter.