I am a new to using Mongo DB and exploring the frameworks around for migrating from mysql to mongodb. So far from my findings I have been able to figure out SpringMongo as the best solution to my requirements.
The only problem is that instead of using a DSL based or abstract querying mechanism, I wished the framework allowed me to pass plain json string as arguments to the different methods exposed by the API(find, findOne) so that the query parameters can be written out to an external file (using a key to refer) and passed to the methods by reading and parsing at run time. But the framework should be capable of mapping the results to the domain objects.
Is there a way in spring-mongo to achieve this? Or is there any other frameworks on the same lines
You could use Spring Data to do that, just use the BasicQuery class instead of Query class. Your code will look like the following:
/* Any arbitrary string that could to parsed to DBObject */
Query q = new BasicQuery("{ filter : true }");
List<Entity> entities = this.template.find(q, Entity.class);
If you want more details:
http://static.springsource.org/spring-data/data-mongo/docs/current/reference/html/#mongo.query
http://static.springsource.org/spring-data/data-mongodb/docs/current/api/org/springframework/data/mongodb/core/query/BasicQuery.html
Well I got to find this one in the Spring data MongoOperations...
String jsonCommand = "{username: 'mickey'}";
MongoOperations mongoOps = //get mongooperations implemantation
mongoOps.executeCommand(jsonCommand)
It returns an instance of CommandResult that encapsulates the result.
Related
I'm the new guy in the GraphQL world and trying to find a way to have multiple Query types or how to split the Query type into multiple files..
I use Hot Chocolate for Asp.Net Core, and everything looks good and works.
But what if I need to combine few queries in one GraphQL API? Some really unrelated stuff, f.e. DogsQuery and CarsQuery.
In Asp.Net, I write similar to:
public void ConfigureServices(IServiceCollection services)
{
services
.AddGraphQLServer()
//.AddQueryType<DogsQuery>()
.AddQueryType<CarsQuery>();
}
It works fine if I use only one Query class simultaneously (Dogs or Cars). But how to use both?
I've searched a lot but can't find the answer.
You cannot have multiple Query/Mutation/Subscription types in graphql, but you can split the types to multiple files in HotChocolate.
You can use the [ExtendObjectType(Name = "Query")] attribute above both your query types. This works for the Subscriptions ([ExtendObjectType(Name = "Subscription")]) and Mutations ([ExtendObjectType(Name = "Mutation")]) the same way.
This attribute is used for merging any two graphql types in the same HotChocolate server. The name value must be the name of the GraphQl type you want to merge your C# class into. In this case it is Query.
After doing that, you can add the types to your server like this:
public void ConfigureServices(IServiceCollection services)
{
services
.AddGraphQLServer()
.AddQueryType(d => d.Name("Query"))
.AddTypeExtension<DogsQuery>()
.AddTypeExtension<CarsQuery>();
}
You can find this and many more useful things in the workshop example on Github:
https://github.com/ChilliCream/graphql-workshop
Using Camunda as the tool for orchestration of the microservices. At later time, I find the process_instances_id generated necessary for continuing a particular process by using it in messageEventReceived(). Code as follows:
val processid = getProcessID(key1, key2)
val runtimeService = processengine.getRuntimeService
val subscription = runtimeService.createEventSubscriptionQuery
.eventType("message")
.eventName(eventname)
.processInstanceId(executionid)
.singleResult
runtimeService.messageEventReceived(subscription.getEventName, subscription.getExecutionId)
As of this moment the processid is saved and then retrieved from the database using the getProcessID(...) function when necessary. Is this proper?
Does camunda already have the list of process_ids in its own database? If so, how do I retrieve a particular process instance id just giving composite key(s)? Is that even possible?
It is the common way. You can also use the public api to get the process instance and his id via the process definition key.
See the following example from the documentation:
runtimeService.createProcessInstanceQuery()
.processDefinitionKey("invoice")
.list();
For your given example there is also a simpler way. It is possible to correlate the message via the runtime service.
See this example from the documenation:
runtimeService.createMessageCorrelation("messageName")
.processInstanceBusinessKey("AB-123")
.setVariable("payment_type", "creditCard")
.correlate();
You can use
runtimeService.createProcessInstanceQuery().list();
the query supports fluent criteria for filtering, for example on process_key, variables, businessKey ...
Could anybody help me to understand what kind of work is going behind the scene, when LINQ is used for retrieving SharePoint objects. For example, I can use a code like this:
private IEnumerable<List> newLists;
var dt = new DateTime(2010, 3, 20);
var query = from list
in clientContext.Web.Lists
where list.Created > dt && list.Hidden == false
select list;
newLists = clientContext.LoadQuery(query);
clientContext.ExecuteQuery();
How does it work?
How does request look like?
From documentation I found:
When you use the CSOM, you can write LINQ queries against client-side
objects, such as lists and Webs, and then use the ClientContext class
to submit these queries to the server. It's important to understand
that when you take this approach, you are using LINQ to Objects to
query SharePoint objects, not LINQ to SharePoint. This means that your
LINQ expressions are not converted to CAML and you will not see the
performance benefits that are associated with CAML conversion.
So, I was little bit confused, because I thought, that LINQ expression is transformed to Caml request. I can't understand how does it work. How can I watch details of request while executing ExecuteQuery() method? Could you please recomend me any tools for watching requests?
SP uses CAML internally: SP runtime converts Linq to CAML and send it via Soap request, or REST statement (if you are using RESTful services): http://msdn.microsoft.com/en-us/library/ff798339.aspx (with examples);
See more here:
http://msdn.microsoft.com/en-us/library/ff798464.aspx
and this can be helpful: http://nikspatel.wordpress.com/2012/08/05/sharepoint-2010-data-querying-options-server-om-vs-client-om-vs-rest-vs-linq-vs-search-api/
I am wondering if it is possible to map a named native query on the fly instead of getting back a list of Object[] and then looping through and setting up the object that way. I have a call which I know ill return a massive data set and I want to be able to map it right to my entity. Can I do that or will I have to continue looping through the result set.
Here is what I am doing now...
List<Provider> ObjList = (List<Provider>) emf.createNativeQuery(assembleQuery(organizationIDs, 5)).getResultList();
That is my entity, the List (my entity is the provider). Normally I would just return a List<Object[]>
and then I would loop through that to get back all the objects and set them up as new providers and add them to a list....
//List<Provider> provList = new ArrayList<Provider>();
/*for(Object[] obj: ObjList)
{
provList.add(this.GetProviderFromObj(obj));
}*/
As you can see I commented that section of the code out to try this out. I know you can map named native queries if you put your native query in the entity itself and then call it via createNamedQuery. I would do it that way, but I need to use the IN oracle keyword because I have a list of ID's that I want to check against. It is not just one that is needed. And as we all know, native queruies don't handle the in keyword to well. Any advice?
Sigh, If only the IN keyword was supported well for NamedNativeQueries.
Assuming that Provider is configured as a JPA entity, you should be able to specify the class as the second parameter to your createNativeQuery call. For example:
List<Provider> ObjList = (List<Provider>) emf.createNativeQuery(assembleQuery(organizationIDs, 5), Provider.class).getResultList();
According to the documentation, "At a minimum, your SQL must select the class' primary key columns, discriminator column (if mapped), and version column (also if mapped)."
See the OpenJPA documentation for more details.
Suppose I have a class Customer that is mapped to the database and everything is a-ok.
Now suppose that I want to retrieve - in my application - the column name that NH knows Customer.FirstName maps to.
How would I do this?
You can access the database field name through NHibernate.Cfg.Configuration:
// cfg is NHibernate.Cfg.Configuration
// You will have to provide the complete namespace for Customer
var persistentClass = cfg.GetClassMapping(typeof(Customer));
var property = persistentClass.GetProperty("FirstName");
var columnIterator = property.ColumnIterator;
The ColumnIterator property returns IEnumerable<NHibernate.Mapping.ISelectable>. In almost all cases properties are mapped to a single column so the column name can be found using property.ColumnInterator.ElementAt(0).Text.
I'm not aware that that's doable.
I believe your best bet would be to use .xml files to do the mapping, package them together with the application and read the contents at runtime. I am not aware of an API which allows you to query hibernate annotations (pardon the Java lingo) at runtime, and that's what you would need.
Update:
Judging by Jamie's solution, NHibernate and Hibernate have different APIs, because the Hibernate org.hibernate.Hibernate class provides no way to access a "configuration" property.