Does ToFuture works with nhibernate linq? If so, how do you use it?
Be carefull ToFuture only works if the database driver supports MulitpleQueries. This is only the case in some drivers (eg. MySql, SqlServer) but not in all (eg. Oracle)
Yes it does. Here's a simple example:
var blogs = _session.Query<Blog>()
.Take(30)
.ToFuture();
var blogCount= _session.Query<Blog>()
.ToFutureValue(x => x.Count());
Console.WriteLine(blogCount.Value); // DB is queried here.
Here's an example of where I've used it for a customer search form that displayed paged search results and and a total count of search results. Notice you can reuse an IQueryable to create two futures. The Filter methods built an IQueryable based on what fields the user searched by.
int resultsPerPage = 50;
var query = _session.Query<CustomerSearch>()
.FilterById(model)
.FilterByFirstName(model)
.FilterByLastName(model)
.FilterBySocialSecurityNumber(model)
.FilterByPrimaryPhoneNumber(model);
var futureResults = query
.OrderBy(x => x.Id)
.Skip(model.Page * resultsPerPage)
.Take(resultsPerPage)
.ToFuture();
var futureCount = query.ToFutureValue(x => x.Count());
Related
I'm running into some n+1 performance issues when iterating over a collection of ContentItems of a custom Type that I created solely through migrations.
ContentDefinitionManager.AlterPartDefinition("MyType", part => part
.WithField("MyField", field => field
...
)
);
ContentDefinitionManager.AlterTypeDefinition("MyType", type => type
.WithPart("MyType")
);
Every time I access a field of this part a new query is performed. I can use QueryHints to avoid this for the predefined parts
var myItems = _orchardServices.ContentManager.Query().ForType("MyType")
.WithQueryHints(new QueryHints().ExpandParts<LocalizationPart()
...
);
but can I do this for the ContentPart of my custom type too? This does not seem to work:
var myItems = _orchardServices.ContentManager.Query().ForType("MyType")
.WithQueryHints(new QueryHints().ExpandParts<ContentPart>()
...
);
How can I tell Orchard to just get everything in one go? I'd prefer to be able to do this without writing my own HQL or directly addressing the repositories.
Example:
var myItems = _orchardServices.ContentManager.Query().ForType("MyType");
#foreach(var item in myItems.Take(100)) {
foreach(var term in item.Content.MyItem.MyTaxonomyField.Terms) {
// Executes 100 queries
<div>#term.Name</div>
}
}
TaxonomyField doesn't store ids and using the TaxonomyService inside of the loop wouldn't improve performance. Right now, to work around this, I fetch all TermContentItems.Where(x => myItems.Select(i => i.Id).Contains(TermPartRecord.Id)) from the repository outside of the loop as well as a list of all the terms of the Taxonomy that the field is using. Then inside the loop:
var allTermsInThisField = termContentItems.Where(tci => tci.TermsPartRecord.Id == c.Id)
.Select(tci => terms.Where(t => t.Id == tci.TermRecord.Id).Single()).ToList()
I'm not a very experienced programmer but this was the only way I could see how to do this without digging into HQL and it seems overly complicated for my purposes. Can Orchard do this in less steps?
I was wondering if there was a way to add an "Order By" clause when retrieving data from Acumatica through the Web Service API?
IN202500Content IN202500 = oScreen.IN202500GetSchema();
oScreen.IN202500Clear();
Command[] oCmd = new Command[] {IN202500.StockItemSummary.ServiceCommands.EveryInventoryID,
IN202500.StockItemSummary.InventoryID,
IN202500.StockItemSummary.Description,
IN202500.StockItemSummary.ItemStatus,
IN202500.GeneralSettingsItemDefaults.ItemClass,
IN202500.GeneralSettingsItemDefaults.LotSerialClass,
IN202500.PriceCostInfoPriceManagement.DefaultPrice,
};
Filter[] oFilter = new Filter[] {new Filter
{
Field = new Field {ObjectName = IN202500.StockItemSummary.InventoryID.ObjectName,
FieldName = "LastModifiedDateTime"},
Condition = FilterCondition.GreaterOrEqual,
Value = SyncDate
}
};
String[][] sReturn = oScreen.IN202500Export(oCmd, oFilter, iMaxRecords, true, false);
I would like to sort the results for example by DefaultPrice, so that I can retrieve the Top 200 most expensive items in my list (using iMaxRecords = 200 in this case)
I haven't seen any parameters that allows me to do the sorting yet.
I ran into this when I developed a round robin assignment system and the short answer is using the Acumatica API you cant do a sort on the results you have to do it outside of the API (This info came from a friend closely tied to the Acumatica product).
I came up with two options:
Query your DB directly... There are always reasons not to do this but it is much faster than pulling the result from the API and will allow you to bypass the BQL Acumatica uses and write an SQL statement that does EXACTLY what you want providing a result that is easier to work with than the jagged array Acumatica sends.
You can use some Linq and build a second array[][] that is sorted by price and then trim it to the top 200 (You would need all results from Acumatica first).
// This is rough but should get you there.
string[][] MaxPriceList = sReturn.OrderBy(innerArray =>
{
if () // This is a test to make sure the element is not null
{
decimal price;
if (//test decimal is not null))
return price;
}
return price.MaxValue;
}).Take(200).ToArray(); //Take 200 is a shot but might work
I am importing products from a product feed. A product has a designer and a category and I made them separate tables (Parse classes).
The problem now is that I need to check if a category or designer already exists so I don't need to create it.
Currently I am not checking it, causing many duplicates in my DB. If I checked in DB, it would be asynchronous but I actually need it to be somehow sequential(serialized).. Any ideas?
for (var i=1;i<productsFromFeed.length;i++){
productId = parseInt(productsFromFeed[i][1]);
if (productId > lastProduct.get("productId")){
console.log("Product is new: " + productId);
var Designer = Parse.Object.extend("Designer");
var Product = Parse.Object.extend("Product");
var Category = Parse.Object.extend("Category");
var designer = new Designer();
designer.set("name", productsFromFeed[i][4]);
designer.set("designerId", parseInt(productsFromFeed[i][5]));
var category = new Category();
category.set("name", productsFromFeed[i][6]);
category.set("categoryId", parseInt(productsFromFeed[i][7]));
var newProduct = new Product();
newProduct.set("productName", productsFromFeed[i][0]);
newProduct.set("productId", parseInt(productsFromFeed[i][1]));
newProduct.set("designer", designer);
newProduct.set("category", category);
objects.push(newProduct);
} else {
console.log("Product already exists: " + productId);
}
}
It doesn't need to be serial, you just need to deal with the asynchronous nature of what you're trying to do - using promises.
You could run a query to find everything in advance and locally cache them, that's only useful if you're doing a bulk import, your code does look like a small bulk import but it isn't clear if this will be an efficient approach.
In your case just run your queries and use promises to chain each logical stage together. Note that for your loop you can put the resulting promises into an array and wait till they're all complete.
I'm trying to retrieve a list of entities from CRM, but I'd like to get each one with the related entities. So far, I've the following code:
FilterExpression filterExpression = new FilterExpression();
ConditionExpression condition = new ConditionExpression(Constants.ModifiedOnAttribute, ConditionOperator.GreaterEqual, lastSync);
filterExpression.AddCondition(condition);
QueryExpression query = new QueryExpression()
{
EntityName = entityName,
ColumnSet = new ColumnSet(attributesMetadata.Select(att => att.Name).ToArray<string>()),
Criteria = filterExpression,
Distinct = false,
NoLock = true
};
RetrieveMultipleRequest multipleRequest = new RetrieveMultipleRequest();
multipleRequest.Query = queryExpression;
RetrieveMultipleResponse response = (RetrieveMultipleResponse)proxy.Execute(multipleRequest);
In the variable response, I can see the EntityCollection attribute, but inside, Related entities always come empty.
I'd like to know if it is possible to retrieve the set of a given entities, with the related entities, using RetrieveMultipleRequest, rather than go one by one using RetrieveRequest.
One approach to retreive related entities data - adding LinkEntities to your query. Example below will make you an idea how to make this:
LinkEntity linkEntity = new LinkEntity("email", "new_emails", "activityid", "new_relatedemail", JoinOperator.Inner);
linkEntity.Columns.AddColumn("versionnumber");
linkEntity.Columns.AddColumn("new_emailsid");
linkEntity.EntityAlias = "related";
query = new QueryExpression("email");
query.ColumnSet.AddColumn("activityid");
query.ColumnSet.AddColumn("versionnumber");
query.Criteria.AddCondition("modifiedon", ConditionOperator.NotNull);
query.LinkEntities.Add(linkEntity);
And then you can access attributes from related entities using EntityAlias you specified above:
foreach (Entity entity in entities.Entities)
{
if ((long)(entity["related.versionnumber"] as AliasedValue).Value > 0)
{
stop = false;
}
}
The RetrieveMultipleRequest is for returning multiple instances of a particular type of entity. I have spent a year using the CRM SDK from C# and I have found no way of populating those related entity collections in a single query. This basically leaves you with two options:
Use the AliasedValue as SergeyS recommends. Remember when querying 1:Many relationships, be aware that you could be returning multiple results for the same parent entity. This is what I use most of the time.
Perform a second query for each relationship you want access to. You'll probably get better performance if you can use an IN statement in your second query, based on the results of the first, rather than performing a separate query for each result of the first.
Below is some pseudo code to show the difference.
var contacts = GetContacts();
// One Request to get the cars for the contacts
var cars = GetCarsWhereContactIdIn(contacts.Select( c => c.new_ContactId));
foreach(var c in contacts){
c.new_Cars.AddRange(cars.where(car => car.new_contactId = c.ContactId));
}
// Verses
var contacts = GetContacts();
foreach(var c in contacts){
// One Request for each contact
c.new_Cars.AddRange(GetCarsForContact(c.ContactId));
}
Why is no SQL being generated when I run my Nhibernate 3 query?
public IQueryable<Chapter> FindAllChapters()
{
using (ISession session = NHibernateHelper.OpenSession())
{
var chapters = session.QueryOver<Chapter>().List();
return chapters.AsQueryable();
}
}
If I run the query below I can see that the SQL that gets created.
public IQueryable<Chapter> FindAllChapters()
{
using (ISession session = NHibernateHelper.OpenSession())
{
var resultDTOs = session.CreateSQLQuery("SELECT Title FROM Chapter")
.AddScalar("Title", NHibernateUtil.String)
.List();
// Convert resultDTOs into IQueryable<Chapter>
}
}
Linq to NHibernate (like Linq to entities) uses delayed execution. You are returning IQueryable<Chapter> which means that you might add further filtering before using the data, so no query is executed.
If you called .ToList() or .List() (i forget which is in the API), then it would actually produce data and execute the query.
In other words, right now you have an unexecuted query.
Added: Also use Query() not QueryOver(). QueryOver is like detached criteria.
For more info, google "delayed execution linq" for articles like this