how to display the some specific columns of table instead of whole table in entity framework.
using (DataEntities cxt = new DataEntities())
{
notes note = cxt.notes.Where(no => no.id == accID).SingleOrDefault();
return notes;
}
For this purpose, I would suggest you to make use of ViewModel like following :-
notes note = cxt.notes.SingleOrDefault(no => no.id == accID);
var model = new YourViewModel // Your viewModel class
{
ID = note.ID,
PropertyOne = note.PropertyOne, // your ViewModel Property
PropertyTwo = note.PropertyTwo
};
You can do this with QueryView.
This implies editing your model directly in XML as there is no designer support for this, but you will get an independant entity with less fields than the original one.
Advantages:
You can then query data base for this truncated entity directly (you will get only fields you need from the data base - no need to get whole entity from DB and trancate it in code)
It is good in scenarios where you want to send this truncated entity to the
client
with WCF to minimize traffic (e.g. when building big lists on client
that basically need only name and ID and no other entity specific
information).
Disadvantages:
This QueryView-based entity is read only. To make it writeable you will have to add r/w functionality yourself
Related
I am using TYPO3 8. In my extension I have a database table "company" in which I store for each company the total number of places (number_places) and the number of occupied places (occupied_places).
Now I want to limit the search to companies which have available places left.
In MySQL it would be like this:
SELECT * FROM company WHERE number_places > occupied_places;
How can I create this query in the extbase repository?
I tried to introduce the virtual property placesLeft in my model but it did not work.
I don't want to use a raw SQL statement as mentioned below, because I already have implemented a filter which uses plenty of different constraints.
Extbase query to compare two fields in same table
You can do it like this in your repository class, please note the comments inside the code:
class CompanyRepository extends \TYPO3\CMS\Extbase\Persistence\Repository
{
public function findWithAvailablePlaces(bool $returnRawQueryResult = false)
{
// Create a QueryBuilder instance
$queryBuilder = $this->objectManager->get(\TYPO3\CMS\Core\Database\ConnectionPool::class)
->getConnectionForTable('company')->createQueryBuilder();
// Create the query
$queryBuilder
->select('*')
->from('company')
->where(
// Note: this string concatenation is needed, because TYPO3's
// QueryBuilder always escapes the value in the ExpressionBuilder's
// methods (eq(), lt(), gt(), ...) and thus render it impossible to
// compare against an identifier.
$queryBuilder->quoteIdentifier('number_places')
. \TYPO3\CMS\Core\Database\Query\Expression\ExpressionBuilder::GT
. $queryBuilder->quoteIdentifier('occupied_places')
);
// Execute the query
$result = $queryBuilder->execute()->fetchAll();
// Note: this switch is not needed in fact. I just put it here, if you
// like to get the Company model objects instead of an array.
if ($returnRawQueryResult) {
$dataMapper = $this->objectManager->get(\TYPO3\CMS\Extbase\Persistence\Generic\Mapper\DataMapper::class);
return $dataMapper->map($this->objectType, $result);
}
return $result;
}
}
Notes:
If you have lots of records to deal with, I would - for performance reasons - not use the data mapping feature and work with arrays.
If you want to use the fluid pagination widget, be sure you don't and build your own pagination. Because of the way this works (extbase-internally), you'd get a huge system load overhead when the table grows. Better add the support for limited db queries to the repository method, for example:
class CompanyRepository extends \TYPO3\CMS\Extbase\Persistence\Repository
{
public function findWithAvailablePlaces(
int $limit = 10,
int $offset = 0,
bool $returnRawQueryResult = false
) {
// ...
$queryBuilder
->setMaxResults($limit)
->setFirstResult($offset);
$result = $queryBuilder->execute()->fetchAll();
// ...
}
}
I think you cant do this using the default Extbase Query methods like equals() and so on. You may use the function $query->statement() for your specific queries like this.
You also can use the QueryBuilder since TYPO3 8 which has functions to compare fields to each other:
https://docs.typo3.org/typo3cms/CoreApiReference/latest/ApiOverview/Database/QueryBuilder/Index.html#quoteidentifier-and-quoteidentifiers
It's fine to use this QueryBuilder inside Extbase repositories. After this you can use the DataMapper to map the query results to Extbase models.
In case of using "statement()" be aware of escaping every value which may cause any kind of SQL injections.
Based on the current architecture of TYPO3, the data structure is such that comparing of two tables or, mixing results from two tables ought to be done from within the controller, by injecting the two repositories. Optionally, you can construct a Domain Service that can work on the data from the two repositories from within the action itself, in the case of a routine. The service will also have to be injected.
Note:
If you have a foreign relation defined in your table configuration, the results of that foreign relation will show in your defined table repository. So, there's that too.
In spring data neo4j I have simple one-to-many relationship: (:User)-[:EMPLOYEE_OF]->(:Company). User can be employee of only one company. Here are my entities:
class User(#Relationship(type = "EMPLOYEE_OF") var company: Company? = null, /* ids etc */)
class Company(/* ids etc */)
When I want to change target of that relationship or remove it neo4j keeps adding new relationships instead of replacing it.
val user = userRepository.findByName("user1")
val company = companyRepository.findByName("company1")
user.company = company
userRepository.save(user)
// 2nd case
user.company = null
userRepository.save(user)
In both cases, relationships are only added, never removed.
Is there a proper way to do it?
You have to put the load / find and the save in a transaction. The best way in a Spring project to do this is to extract the logic into a service layer method of your application and mark it as #Transactional.
Within this transaction, Spring Data Neo4j / Neo4j-OGM can track the changes that happen on the node and change or remove the relationships.
I'm using early-bound entities, generated by CrmSvcUtil, and I'm testing the SDK by retrieving an account entity:-
var account = myContext.AccountSet.FirstOrDefault(o => o.Id == Guid.Parse("..."));
(BTW is there an easier way to retrieve an entity by ID?!)
Looking at the account object that is returned, I can see various properties of type OptionSetValue (e.g. "PreferredContactMethodCode"). How do I get the actual item from this OptionSetValue object?
Similarly, there are numerous properties of type EntityReference, which contains an Id and LogicalName (the entity name I presume). How can I populate such a property - is it one of the Get... methods? And do these have to be called separately, or is it possible to "pre-fetch" certain relationships as part of the initial query that retrieves the account entity?
Similarly with the various IEnumerable<> properties (which presumably correspond to 1-M entity relationships), e.g. a property called "opportunity_customer_accounts" of type IEnumerable. How do I populate one of these properties? And (again) does this have to be done as a separate query/method call, or can it be "pre-fetched"?
Retrieve
I'm not really sure how much simpler the retrieve operation could get but for a single record the user of the context is probably overkill. So you could retrieve a specific record where you know directly with the IOrganizationService:
account = service.Retrieve("account", Guid.Parse("..."), new ColumnSet(true));
Option Set Labels
For the OptionSet labels you can look at my answer here: How to get the option set from a field in an entity in CRM 2011 using crm sdk and C#.
If you need the label for multiple OptionSet's on an entity you may want to just retrieve the Entity's metadata once (http://srinivasrajulapudi.blogspot.com/2012/01/retrieve-entity-metadata-in-crm-2011.html):
string entityName ="contact";
// Get the metadata for the currently list's entity
// This metadata is used to create a "Property Descriptor Collection"
RetrieveEntityRequest mdRequest = new RetrieveEntityRequest ( )
{ EntityFilters = EntityFilters.All,
LogicalName = entityName,
RetrieveAsIfPublished = false
};
// Execute the request
RetrieveEntityResponse entityResponse = ( RetrieveEntityResponse ) this.ServiceProxy.Execute ( mdRequest );
EntityMetadata entityData = entityResponse.EntityMetadata;
//To Get Option Set Data
var preferdList= ( entityData.Attributes.Where ( p => p.LogicalName == "preferredcontactmethodcode" ) ).ToList ( ).FirstOrDefault ( ); ;
if ( preferdList != null ) {
PicklistAttributeMetadata optionList= preferdList as PicklistAttributeMetadata;
OptionSetMetadata opValues= optionList.OptionSet;
foreach ( var op in opValues.Options ) {
preferedMethod.Add ( new OptionSet { Value = op.Value.Value, Text = op.Label.LocalizedLabels[0].Label.ToString() } );
}
}
EntityReference()
To set an EntityReference typed field:
account.primarycontact = new EntityReference("contact", Guide.Parse("..."));
If they have a value and you requested the column in your ColumnSet() they should be populated, so I'm not really sure I understand your question. If you mean, you want the full record then you need to do a service.Retrieve(...) for the record.
Related Entities (i.e., opportunity_customer_accounts)
This is where using an OrganizationServiceContext makes life easier (https://msdn.microsoft.com/en-us/library/gg695791.aspx):
context.LoadProperty(contact, "transactioncurrency_contact");
// read related entity dynamically
var currency = contact.GetRelatedEntity("transactioncurrency_contact");
Console.WriteLine(currency.GetAttributeValue("currencyname"));
// read related entity statically
var currencyStatic = contact.transactioncurrency_contact;
Console.WriteLine(currencyStatic.CurrencyName);
If you are not using an OrganizationServiceContext you can try using a QueryExpression using LinkedEntities, although I've never done this to populate an early-bound entity so I don't know if it works (perhaps someone will add a comment with the answer.)
I have a document in RavenDB that looks looks like:
{
"ItemId": 1,
"Title": "Villa
}
With the following metadata:
Raven-Clr-Type: MyNamespace.Item, MyNamespace
Raven-Entity-Name: Doelkaarten
So I serialized with a type MyNamespace.Item, but gave it my own Raven-Entity-Name, so it get its own collection.
In my code I define an index:
public class DoelkaartenIndex : AbstractIndexCreationTask<Item>
{
public DoelkaartenIndex()
{
// MetadataFor(doc)["Raven-Entity-Name"].ToString() == "Doelkaarten"
Map = items => from item in items
where MetadataFor(item)["Raven-Entity-Name"].ToString() == "Doelkaarten"
select new {Id = item.ItemId, Name = item.Title};
}
}
In the Index it is translated in the "Maps" field to:
docs.Items
.Where(item => item["#metadata"]["Raven-Entity-Name"].ToString() == "Doelkaarten")
.Select(item => new {Id = item.ItemId, Name = item.Title})
A query on the index never gives results.
If the Maps field is manually changed to the code below it works...
from doc in docs
where doc["#metadata"]["Raven-Entity-Name"] == "Doelkaarten"
select new { Id = doc.ItemId, Name=doc.Title };
How is it possible to define in code the index that gives the required result?
RavenDB used: RavenHQ, Build #961
UPDATE:
What I'm doing is the following: I want to use SharePoint as a CMS, and use RavenDB as a ready-only replication of the SharePoint list data. I created a tool to sync from SharePoint lists to RavenDB. I have a generic type Item that I create from a SharePoint list item and that I serialize into RavenDB. So all my docs are of type Item. But they come from different lists with different properties, so I want to be able to differentiate. You propose to differentiate on an additional property, this would perfectly work. But then I will see all list items from all lists in one big Items collection... What would you think to be the best approach to this problem? Or just live with it? I want to use the indexes to create projections from all data in an Item to the actual data that I need.
You can't easily change the name of a collection this way. The server-side will use the Raven-Entity-Name metadata, but the client side will determine the collection name via the conventions registered with the document store. The default convention being to use the type name of the entity.
You can provide your own custom convention by assigning a new function to DocumentStore.Conventions.FindTypeTagName - but it would probably be cumbersome to do that for every entity. You could create a custom attribute to apply to your entities and then write the function to look for and understand that attribute.
Really the simplest way is just to call your entity Doelkaarten instead of Item.
Regarding why the change in indexing works - it's not because of the switch in linq syntax. It's because you said from doc in docs instead of from doc in docs.Items. You probably could have done from doc in docs.Doelkaartens instead of using the where clause. They are equivalent. See this page in the docs for further examples.
I use as a front-end sproutcore, and as back-end an nhibernate driven openrasta REST solution.
In sproutcore, references are actualy ID's / guid's. So an Address entity in the Sproutcore model could be:
// sproutcore code
App.Address = App.Base.extend(
street: SC.Record.attr(String, { defaultValue: "" }),
houseNumber: SC.Record.attr(String),
city: SC.Record.toOne('Funda.City')
);
with test data:
Funda.Address.FIXTURES = [
{ guid: "1",
street: "MyHomeStreet",
houseNumber: "34",
city: "6"
}
]
Here you see that the reference city has a value of 6. When, at some point in your program, you want to use that reference, it is done by:
myAddress.Get("city").MyCityName
So, Sproutcore automatically uses the supplied ID in a REST Get, and retrieves the needed record. If the record is available in de local memory of the client (previously loaded), then no round trip is made to the server, otherwise a http get is done for that ID : "http://servername/city/6". Very nice.
Nhibernate (mapped using fluent-nhibernate):
public AddressMap()
{
Schema(Config.ConfigElement("nh_default_schema", "Funda"));
Not.LazyLoad();
//Cache.ReadWrite();
Id(x => x.guid).Unique().GeneratedBy.Identity();
Table("Address");
Map(x => x.street);
Map(x => x.houseNumber);
References(x => x.city,
"cityID").LazyLoad().ForeignKey("fk_Address_cityID_City_guid");
}
Here i specified the foreign key, and to map "cityID" on the database table. It works ok.
BUT (and these are my questions for the guru's):
You can specify to lazy load / eager load a reference (city). Off course you do not want to eager load all your references. SO generally your tied to lazy loading.
But when Openrast (or WCF or ...) serializes such an object, it iterates the properties, which causes all the get's of the properties to be fired, which causes all of the references to be lazy loaded.
SO if your entity has 5 references, 1 query for the base object, and 5 for the references will be done. You might better be off with eager loading then ....
This sucks... Or am i wrong?
As i showed how the model inside sproutcore works, i only want the ID's of the references. So i Don't want eagerloading, and also not lazy loading.
just a "Get * from Address where ID = %" and get that mapped to my Address entity.
THen i also have the ID's of the references which pleases Sproutcore and me (no loading of unneeded references). But.... can NHibernate map the ID's of the references only?
And can i later indicate nHibernate to fully load the reference?
One approach could be (but is not a nice one) to load all reference EAGER (with join) (what a waste of resources.. i know) and in my Sever-side Address entity:
// Note: NOT mapped as Datamember, is NOT serialized!
public virtual City city { get; set; }
Int32 _cityID;
[Datamember]
public virtual Int32 cityID
{
get
{
if (city != null)
return city .guid;
else
return _cityID;
}
set
{
if (city!= null && city.guid != value)
{
city= null;
_cityID = value;
}
else if (city == null)
{
_cityID = value;
}
}
}
So i get my ID property for Sproutcore, but on the downside all references are loaded.
A better idea for me???
nHibernate-to-linq
3a. I want to get my address without their references (but preferably with their id's)
Dao myDao = new Dao();
from p in myDao.All()
select p;
If cities are lazy loading in my mapping, how can i specify in the linq query that i want it also to include my city id only?
3b.
I want to get addresses with my cities loaded in 1 query: (which are mapped as lazyloaded)
Dao myDao = new Dao();
from p in myDao.All()
join p.city ???????
select p;
My Main Question:
As argued earlier, with lazy loading, all references are lazy loaded when serializing entities. How can I prevent this, and only get ID's of references in a more efficient way?
Thank you very much for reading, and hopefully you can help me and others with the same questions. Kind regards.
as a note you wrote you do this
myAddress.Get("city").MyCityName
when it should be
myAddress.get("city").get("MyCityName")
or
myAddress.getPath("city.MyCityName")
With that out of the way, I think your question is "How do I not load the city object until I want to?".
Assuming you are using datasources, you need to manage in your datasource when you request the city object. So in retrieveRecord in your datasource simply don't fire the request, and call dataSourceDidComplete with the appropriate arguments (look in the datasource.js file) so the city record is not in the BUSY state. You are basically telling the store the record was loaded, but you pass an empty hash, so the record has no data.
Of course the problem with this is at some point you will need to retrieve the record. You could define a global like App.WANTS_CITY and in retrieveRecords only do the retrieve when you want the city. You need to manage the value of that trigger; statecharts are a good place to do this.
Another part of your question was "How do I load a bunch of records at once, instead of one request for each record?"
Note on the datasource there is a method retrieveRecords. You can define your own implementation to this method, which would allow you to fetch any records you want -- that avoids N requests for N child records -- you can do them all in one request.
Finally, personally, I tend to write an API layer with methods like
getAddress
and
getCity
and invoke my API appropriately, when I actually want the objects. Part of this approach is I have a very light datasource -- I basically bail out of all the create/update/fetch methods depending on what my API layer handles. I use the pushRetrieve and related methods to update the store.
I do this because the store uses in datasources in a very rigid way. I like more flexibility; not all server APIs work in the same way.