I have recently started evaluating Dapper as a potential replacement for EF, since I was not too pleased with the SQL that was being generated and wanted more control over it. I have a question regarding mapping a complex object in my domain model. Let's say I have an object called Provider, Provider can contain several properties of type IEnumerable that should only be accessed by going through the parent provider object (i.e. aggregate root). I have seen similar posts that have explained using the QueryMultiple and a Map extension method but was wondering how if I wanted to write a method that would bring back the entire object graph eager loaded, if Dapper would be able to do this in one fell swoop or if it needed to be done piece-meal. As an example lets say that my object looked something like the following:
public AggregateRoot
{
public int Id {get;set;}
...//simple properties
public IEnumerable<Foo> Foos
public IEnumerable<Bar> Bars
public IEnumerable<FooBar> FooBars
public SomeOtherEntity Entity
...
}
Is there a straightforward way of populating the entire object graph using Dapper?
I have a similar situation. I made my sql return flat, so that all the sub objects come back. Then I use the Query<> to map the full set. I'm not sure how big your sets are.
So something like this:
var cnn = sqlconnection();
var results = cnn.Query<AggregateRoot,Foo,Bars,FooBar,someOtherEntity,AggregateRoot>("sqlsomething"
(ar,f,b,fb,soe)=>{
ar.Foo = f;
ar.Bars = b;
ar.FooBar = fb;
ar.someotherentity = soe;
return ar;
},.....,spliton:"").FirstOrDefault();
So the last object in the Query tag is the return object. For the SplitOn, you have to think of the return as a flat array that the mapping will run though. You would pick the first return value for each new object so that the new mapping would start there.
example:
select ID,fooid, foo1,foo2,BarName,barsomething,foobarid foobaritem1,foobaritem2 from blah
The spliton would be "ID,fooid,BarName,foobarid". As it ran over the return set, it will map the properties that it can find in each object.
I hope that this helps, and that your return set is not too big to return flat.
Related
This is my structure of the firestore database:
Expected result: to get all the jobs, where in the experience array, the lang value is "Swift".
So as per this I should get first 2 documents. 3rd document does not have experience "Swift".
Query jobs = db.collection("Jobs").whereArrayContains("experience.lang","Swift");
jobs.get().addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
#Override
public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
//Always the queryDocumentSnapshots size is 0
}
});
Tried most of the answers but none worked out. Is there any way to query data in this structure? The docs only available for normal array. Not available for array of custom object.
Actually it is possible to perform such a query when having a database structure like yours. I have replicated your schema and here are document1, document2, and document3.
Note that you cannot query using partial (incomplete) data. You are using only the lang property to query, which is not correct. You should use an object that contains both properties, lang and years.
Seeing your screenshot, at first glance, the experience array is a list of HashMap objects. But here comes the nicest part, that list can be simply mapped into a list of custom objects. Let's try to map each object from the array to an object of type Experience. The model contains only two properties:
public class Experience {
public String lang, years;
public Experience() {}
public Experience(String lang, String years) {
this.lang = lang;
this.years = years;
}
}
I don't know how you named the class that represents a document, but I named it simply Job. To keep it simple, I have only used two properties:
public class Job {
public String name;
public List<Experience> experience;
//Other prooerties
public Job() {}
}
Now, to perform a search for all documents that contain in the array an object with the lang set to Swift, please follow the next steps. First, create a new object of the Experience class:
Experience firstExperience = new Experience("Swift", "1");
Now you can query like so:
CollectionReference jobsRef = rootRef.collection("Jobs");
jobsRef.whereArrayContains("experience", firstExperience).get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
#Override
public void onComplete(#NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
for (QueryDocumentSnapshot document : task.getResult()) {
Job job = document.toObject(Job.class);
Log.d(TAG, job.name);
}
} else {
Log.d(TAG, task.getException().getMessage());
}
}
});
The result in the logcat will be the name of document1 and document2:
firstJob
secondJob
And this is because only those two documents contain in the array an object where the lang is set to Swift.
You can also achieve the same result when using a Map:
Map<String, Object> firstExperience = new HashMap<>();
firstExperience.put("lang", "Swift");
firstExperience.put("years", "1");
So there is no need to duplicate data in this use-case. I have also written an article on the same topic
How to map an array of objects from Cloud Firestore to a List of objects?
Edit:
In your approach it provides the result only if expreience is "1" and lang is "Swift" right?
That's correct, it only searches for one element. However, if you need to query for more than that:
Experience firstExperience = new Experience("Swift", "1");
Experience secondExperience = new Experience("Swift", "4");
//Up to ten
We use another approach, which is actually very simple. I'm talking about Query's whereArrayContainsAny() method:
Creates and returns a new Query with the additional filter that documents must contain the specified field, the value must be an array, and that the array must contain at least one value from the provided list.
And in code should look like this:
jobsRef.whereArrayContainsAny("experience", Arrays.asList(firstExperience, secondExperience)).get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
#Override
public void onComplete(#NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
for (QueryDocumentSnapshot document : task.getResult()) {
Job job = document.toObject(Job.class);
Log.d(TAG, job.name);
}
} else {
Log.d(TAG, task.getException().getMessage());
}
}
});
The result in the logcat will be:
firstJob
secondJob
thirdJob
And this is because all three documents contain one or the other object.
Why am I talking about duplicating data in a document it's because the documents have limits. So there are some limits when it comes to how much data you can put into a document. According to the official documentation regarding usage and limits:
Maximum size for a document: 1 MiB (1,048,576 bytes)
As you can see, you are limited to 1 MiB total of data in a single document. So storing duplicated data will only increase the change to reach the limit.
If i send null data of "exprience" and "swift" as "lang" will it be queried?
No, will not work.
Edit2:
whereArrayContainsAny() method works with max 10 objects. If you have 30, then you should save each query.get() of 10 objects into a Task object and then pass them one by one to the to the Tasks's whenAllSuccess(Task... tasks).
You can also pass them directly as a list to Tasks's whenAllSuccess(Collection> tasks) method.
With your current document structure, it's not possible to perform the query you want. Firestore does not allow queries for individual fields of objects in list fields.
What you would have to do is create an additional field in your document that is queryable. For example, you could create a list field with only the list of string languages that are part of the document. With this, you could use an array-contains query to find the documents where a language is mentioned at least once.
For the document shown in your screenshot, you would have a list field called "languages" with values ["Swift", "Kotlin"].
Hiy!
I want all objects(rows in Test Type) with ModelService
So I could iterate through collection and update a Single row (object)'s attribute with new value
I see getModelService.create(TestModel.class) and getModelService.save()
but will they not create a new object/row rather than update a existing object?right
I don't want to create a new one rather selecting one of the existing matching my criteria and update one attribute of that
can somebody help with List<TestModel> testModels = getModelService.get(TestModel.class) will that return me all rows (collection) of Test Type/Table?
unfortunately I can't test it so need help
Actually I am in validateInterceptor ... and on the basis of this intercepted model changed attribute value I have to update another model attribute value...
thanks
ModelService.create(new TestModel.class) will create a single instance of the specified type and attach it to the modelservice's context.
But it will only be saved to the persistence store when you call modelService.save(newInstance)
ModelService.get() returns a model object but expects a Jalo object as input, (Jalo being the legacy persistence layer of hybris) so that won't work for you.
To retrieve objects you can either write your own queries using the FlexibleSearchService or you can have a look at the DefaultGenericDao which has a bunch of simple find() type of methods.
Typically you would inject the dao like e.g.:
private GenericDao<TestModel> dao;
[...]
public void myMethod()
{
List<TestModel> allTestModels = dao.find();
[...]
}
There are a lot more methods with which you can create WHERE type of statements to restrict your result.
Regarding ValidateInterceptor:
Have a look at the wiki page for the lifecycle of interceptors:
https://wiki.hybris.com/display/release5/Interceptors
It's not a good idea to modify 'all' objects of a type while being an interceptor of that type.
So if you're in an interceptor declared for the Test item type, then don't try to modify the items there.
If you happen to be in a different interceptor and want to modify items of a different type:
E.g. you have Type1 which has a list of Type2 objects in it and in the interceptor for Type1 you want to modify all Type2 objects.
For those scenarios you would have to add the instances of Type2 that you modify to the interceptor context so that those changes will be persisted.
That would be something like:
void onValidate(Test1 model, InterceptorContext ctx) throws InterceptorException
{
...
List<Type2> type2s = dao.find();
for (Type2 type2 : type2s)
{
// do something with it
// then make sure to persist that change
ctx.registerElementFor(type2, PersistenceOperation.SAVE);
[...]
}
}
First of all - i think it's not a good idea, to create/update models in any interceptor, especially in 'validation' one.
Regarding your question:
ModelService in most of the cases works with single model, and
designed for create/update/delete operations.
To retreive all models of certain type, you have to use FlexibleSearchService
Then to update each retrieved TestType model, you can use ModelService's save method.
A query to retreive all TestType models will look like:
SELECT PK FROM {TestType}
You could simply use the Flexible Search Service search by example method, and the model service to save them all. Here is an example using Groovy script, with all products :
import java.util.List
import de.hybris.platform.core.model.product.ProductModel
import de.hybris.platform.servicelayer.search.FlexibleSearchService
import de.hybris.platform.servicelayer.model.ModelService
FlexibleSearchService fsq = spring.getBean("flexibleSearchService")
ModelService ms = spring.getBean("modelService")
ProductModel prd = ms.create(ProductModel.class)
List<ProductModel> products = fsq.getModelsByExample(prd)
//Do Whatever you want with the objects in the List
ms.saveAll(products)
I am beginning to use Dapper and love it so far. However as i venture further into complexity, i have ran into a big issue with it. The fact that you can pass an entire custom object as a parameter is great. However, when i add another custom object a a property, it no longer works as it tries to map the object as a SQL parameter. Is there any way to have it ignore custom objects that are properties of the main object being passed thru? Example below
public class CarMaker
{
public string Name { get; set; }
public Car Mycar { get; set; }
}
propery Name maps fine but property MyCar fails because it is a custom object. I will have to restructure my entire project if Dapper can't handle this which...well blows haha
Dapper extensions has a way to create custom maps, which allows you to ignore properties:
public class MyModelMapper : ClassMapper<MyModel>
{
public MyModelMapper()
{
//use a custom schema
Schema("not_dbo_schema");
//have a custom primary key
Map(x => x.ThePrimaryKey).Key(KeyType.Assigned);
//Use a different name property from database column
Map(x=> x.Foo).Column("Bar");
//Ignore this property entirely
Map(x=> x.SecretDataMan).Ignore();
//optional, map all other columns
AutoMap();
}
}
Here is a link
There is a much simpler solution to this problem.
If the property MyCar is not in the database, and it is probably not, then simple remove the {get;set;} and the "property" becomes a field and is automatically ignored by DapperExtensions. If you are actually storing this information in a database and it is a multi-valued property that is not serialized into a JSON or similar format, I think you are probably asking for complexity that you don't want. There is no sql equivalent of the object "Car", and the properties in your model must map to something that sql recognizes.
UPDATE:
If "Car" is part of a table in your database, then you can read it into the CarMaker object using Dapper's QueryMultiple.
I use it in this fashion:
dynamic reader = dbConnection.QueryMultiple("Request_s", param: new { id = id }, commandType: CommandType.StoredProcedure);
if (reader != null)
{
result = reader.Read<Models.Request>()[0] as Models.Request;
result.reviews = reader.Read<Models.Review>() as IEnumerable<Models.Review>;
}
The Request Class has a field as such:
public IEnumerable<Models.Review> reviews;
The stored procedure looks like this:
ALTER PROCEDURE [dbo].[Request_s]
(
#id int = null
)
AS
BEGIN
SELECT *
FROM [biospecimen].requests as bn
where bn.id=coalesce(#id, bn.id)
order by bn.id desc;
if #id is not null
begin
SELECT
*
FROM [biospecimen].reviews as bn
where bn.request_id = #id;
end
END
In the first read, Dapper ignores the field reviews, and in the second read, Dapper loads the information into the field. If a null set is returned, Dapper will load the field with a null set just like it will load the parent class with null contents.
The second select statement then reads the collection needed to complete the object, and Dapper stores the output as shown.
I have been implementing this in my Repository classes in situations where a target parent class has several child classes that are being displayed at the same time.
This prevents multiple trips to the database.
You can also use this approach when the target class is a child class and you need information about the parent class it is related to.
I am new to BreezeJS and would like to know if there are any examples on how to use Breeze with an SQL Stored Procedure?
We have some pretty complex queries and want to be able to call them via an SP. Also, how can we tell Breeze that a column returned from a SP is the Key? We don't want to use Views, because we need to pass variables to the SP query each time we call it.
Thanks.
bob
Ok, the basic idea would be to use Breeze's EntityQuery.withParameters method to pass parameters to a server side method that calls your stored proc and returns an IEnumerable. ( i.e. the result of the stored proc).
If you want to treat this result as collection of Breeze entities then you will either need to shape the results into an existing entity type that Breeze knows about from Metadata OR manually create and add a new EntityType on the client that matches the shape that you want to return.
You may want to look at the EntityQuery.toType method to force breeze to convert your returned data into a specific EntityType or you might alternately want to use a "jsonResultsAdapter" to do the same thing.
Any data that is returned from a query and is converted into an Breeze EntityType is automatically wrapped according the "modelLibrary" in use, i.e. Knockout, Angular, Backbone etc.
If breeze is not able to construct entities out of the returned data then it will still be returned but without any special processing to wrap the result.
Hope this helps!
A sample to access Sql Stored Procedures from Breeze; the store procedure (GoStoCde) has been imported by EF.
Breeze Controller :
[HttpGet]
public object GetCdes(long jprod, int jqte, long jorder)
{
//output params
var owrk = new System.Data.Objects.ObjectParameter("wkres", typeof(string));
owrk.Value = "";
var oeror = new System.Data.Objects.ObjectParameter("ceror", typeof(int));
oeror.Value = 0;
//invoke stored procedure
var envocde = _contextProvider.Context.GoStoCde(jprod, jqte, jorder, owrk, oeror);
//stored procedure results
var cdeResult = new {
dwork = owrk.Value,
deror = oeror.Value,
};
return new { cdeResult };
}
Datacontext :
function reqLnecde(iprod, iqte, iorder, vxeror) {
logger.log("commande en cours...");
var query = new EntityQuery.from("GetCdes")
.withParameters({ jprod: iprod, jqte: iqte, jorder: iorder });
return manager
.executeQuery(query)
.then(querySucceeded)
.fail(cqueryFailed);
function querySucceeded(data) {
//stored procedure results
vxeror(data.results[0]);
//stored procedure object member value
keror = vxeror().cdeResult.deror;
if (keror === 0) {
logger.log("commande done");
} else {
logger.log("article absent");
}
}
function queryFailed(data) {
logger.log("commande failed"); //server errors
}
}
If you prefer to return entity in lieu of object, code consequently and its must also work.
Hope this helps!
Not really an answer here, just a few thoughts.
I think that the ability to return arbitrarily shaped data (read viewmodel) through the use of a stored procedure using withParameters would be an excellent way to inegerate with something like dapper.net. Upon resubmission of said viewmodel you could use the overloads to reconstruct actual entities out of your viewmodel and save changes. The only problem I have though is that one would need a way to easily and automaticaly rerun the sproc and send the data back to the client...
I would like to know if this makes sense to anyone else and/or if anyone has done it already.
For this sort of scenario I would think that you would need to disable the tracking features provided by breeze and/or write a smart enough data service that can handle the viewmodels in such a way that the javascript on the client knows when adding/removing/updating parts x,y,z of viewmodel a that you create objects jx, jy, jz (j for javascript) and submit them back and save as you go (reverse idea of what was mentioned above in a way)
Thoughts?
Is there any way to define the SQL conversion component for additional functions to Linq2Entities.
For example:
myQuery.Where(entity => entity.Contains('foo', SearchFlags.All))
Ideally I am looking for something that doesn't require editing and building a new version the EntityFramework.dll directly. Is there any way to allow extension methods to entity framework that can support SQL generation.
So far I have a template which would represent the method I need to replace for LINQ to Entities:
public static bool Contains(this object source, string searchTerms, SearchFlags flags)
{
return true;
}
Of course this causes the error:
LINQ to Entities does not recognize the method 'Boolean
CONTAINS(System.Object, System.String, SearchFlags)' method, and this method
cannot be translated into a store expression.
To be clear, I don't want to do:
myQuery.AsEnumerable().Where(entity => entity.Contains('foo', SearchFlags.All))
Because I want to be able to execute code in SQL space and not return all the entities manually.
I also cannot use the .ToString() of the IQueryable and execute it manually because I need Entity Framework to populate the objects from several .Include joins.
I don't understand your Q clearly. However if your problem is that you can't use your own methods or other linq to objects method, just use .AsEnumerable() and do your other jobs through linq to objects, not L2E:
myQuery.AsEnumerable().Where(entity => entity.Contains('foo', SearchFlags.All))
And if you need to use your myQuery several times somewhere else, first load it to memory, then use it as many as you want:
var myQuery = from e in context.myEntities
select d;
myQuery.Load();
// ...
var myOtherQuery = from d in context.myEntities.Local
select d;
// Now any L2O method is supported...
I ended up doing the following (which works but is very far from perfect):
All my entities inherit from an IEntity which defines long Id { get; set; }
I then added a redundant restriction
context.myEntities.Where(entity => entity.Id != 0) this is
redundant since the identity starts at 1, but Linq2Entities doesn't
know that.
I then call .ToString() on the IQueryable after I have done all
my other queries, since it is of type DBQuery<Entity> it returns
the SQL Command Text, I do a simple replace with my query restriction.
In order to get all the .Include(...) to work I actually execute
two different sql commands. There is no other more pretty way to tap into this because of query execution plan caching causes issues otherwise (even when disabled).
As a result my code looks like this:
public IQueryable<IEntity> MyNewFunction(IQueryable<IEntity> myQueryable, string queryRestriction)
{
string rawSQL = myQueryable.Select(entity => entity.Id).ToString().Replace("[Extent1].Id <> 0", queryRestriction);
List<long> ids = // now execute rawSQL, get the list of ids;
return myQuerable.Where(entity => ids.Contains(entity.Id));
}
In short, other than manually executing the SQL or running a similar SQL command and appending the restriction using the existing commands the only way to write your own methods to Linq-to-Entities is to manually alter and build your own EntityFramework.dll from the EF6 source.