NHibernate AddOrder on related entity property - nhibernate

I have a search form and result list. The form allows the user to search on the entity properties and related entity properties.
NameContains
EmailContains
CompanyNameContains
The result list displays the contact properties and the relevant related properties, in this case company name
Name | Phone | Email | Company
Company is a relation and for this scenario the relation is eager loaded. Everything is working fine for the search side, filtered results, paging, etc.
I'm using DetachedCriteria and I can only get the sorting to work on Contact properties. (actually don't need sorting on the emails and phone numbers really). I am having trouble sorting on Company Name which is the related property. I wondered if anyone could point me in the right direction. Thanks in advance for you assistance.

Hmm, I would think that something like this should do the trick
(the code below is not verified for syntax, since I was just about to shut down my pc, and I didn't wanted to restart VS.NET (lazy)
DetachedCriteria crit = DetachedCriteria.For<Contact>();
...
crit.CreateAlias ("Company", "c");
crit.AddOrder (Order.Asc("c.CompanyName"));
Something like that ?
At least, that is what I would try ...

Related

Entity joining in xml

I have run into a little roadblock in regards to joining mantle entities. I would like to have a single depicting fields from two mantle entities, but am unsuccessful in joining them. Specifically, I have linked a list of party relationships (as contacts) to a single partyId (vendor), with the goal to make a vendor contacts page. However I am unable to link that form-list with the PartyContactMech and ContactMech entities (in order to display email and phone number in the same form-list). More generally, my question is how can one map lists to each other the same way one can map a list to a single object (using entity-find-one and value-field does not work when tried with entity-find)?
There is no need to make a view-entity (join entities) to do that. Simply do a query on the PartyRelationship entity in the main 'actions' part of your screen specifying the toParty (vendor). Then in your Form-List, use 'row-actions' to query the PartyContactMech and so on for each fromPartyId (contact) entry that the previous query returned. Also have a look at the PartyViewEntities file in Mantle USL. There are some helpful view-enties already defined for you there such as PartyToAndRelationship, PartyFromAndRelationship etc. Also note that entity-find-one returns a single "map" (value-field) as it queries on the PK. Whereas entity-find returns a list of maps (list). They are separate query types. If I understand your question correctly.

How to determine number of children of a record?

Good afternoon everyone!
I'm studying NHibernate, and decided to make some changes. Among them, I noticed that some fields are unnecessary. So I bring my doubt:
I have a list, let's call it Class_List within each study class, I can have N students for each class. Within the list Class_List, I also have other properties as simple as the name of the class.
How I see it is unnecessary to store how many students I have in the database, I would, in a single query, how many records I have. This, using NHibernate.
Is this possible? How?
Best regards,
Gustavo.
Edit: I've forgot to say one thing... I want to return this number of record, as a column. But this column is not mapped in my .hbm.xml file.
If students are mapped as a collection on Class, you can try using something like this:
var numberOfStudents = session.CreateCriteria<Class>()
.Add(Restrictions.IdEq(1))
.CreateCriteria("_students", "students")
.SetProjection(Projections.RowCount())
.UniqueResult<Int32>();
Where '1' is the id of the class (you can use other property) and '_students' is the name of the students collection.

Selecting specific joined record from findAll() with a hasMany() include

(I tried posting this to the CFWheels Google Group (twice), but for some reason my message never appears. Is that list moderated?)
Here's my problem: I'm working on a social networking app in CF on Wheels, not too dissimilar from the one we're all familiar with in Chris Peters's awesome tutorials. In mine, though, I'm required to display the most recent status message in the user directory. I've got a User model with hasMany("statuses") and a Status model with belongsTo("user"). So here's the code I started with:
users = model("user").findAll(include="userprofile, statuses");
This of course returns one record for every status message in the statuses table. Massive overkill. So next I try:
users = model("user").findAll(include="userprofile, statuses", group="users.id");
Getting closer, but now we're getting the first status record for each user (the lowest status.id), when I want to select for the most recent status. I think in straight SQL I would use a subquery to reorder the statuses first, but that's not available to me in the Wheels ORM. So is there another clean way to achieve this, or will I have to drag a huge query result or object the statuses into my CFML and then filter them out while I loop?
You can grab the most recent status using a calculated property:
// models/User.cfc
function init() {
property(
name="mostRecentStatusMessage",
sql="SELECT message FROM statuses WHERE userid = users.id ORDER BY createdat DESC LIMIT 1,1"
);
}
Of course, the syntax of the SELECT statement will depend on your RDBMS, but that should get you started.
The downside is that you'll need to create a calculated property for each column that you need available in your query.
The other option is to create a method in your model and write custom SQL in <cfquery> tags. That way is perfectly valid as well.
I don't know your exact DB schema, but shouldn't your findAll() look more like something such as this:
statuses = model("status").findAll(include="userprofile(user)", where="userid = users.id");
That should get all statuses from a specific user...or is it that you need it for all users? I'm finding your question a little tricky to work out. What is it you're exactly trying to get returned?

Modeling related entities with SQL Server and entity framework

I've got a table in my database storing items:
Items
-------
ItemID
Name
...
Etc
and a separate table storing the PK of two different items from the first table. I want to be able to list the one item, and then any number of related items. I've tried searching for examples but haven't found much surprisingly...
RelatedItems
------------
ItemID
RelatedItemID
If I have four products, whose IDs are 1, 2, 3 and 4... and 1 is related to 2 and 3 I might have data that looks like this:
ItemID RelatedItemID
1 2
1 3
4 1
I am then modeling them in the Entity Framework Designer, and the designer automatically adds an association from the Items table to itself (many to many). The designer also adds two navigation properties, if I use the first property on Item #1 I get all items where Item #1 is in the first column, and if I use the second property I get all the items where Item #1 is in the second column.
I however just want to have one navigation property where I can say Items.RelatedItems and it returns all the items that the above two properties would when combined. I know I can join the two results after the fact but I can't help to think I'm doing something wrong and there is a better way.
Hopefully this is all clear enough.
It sounds like SQL schemas just aren't very good at modeling the concept you're looking for. The schema you've chosen would work well if you want to establish a directional relationship (item A is related to item B, but item B may or may not be related to item A). If you were looking for a grouping-style relationship (Items A and B are in the same group), I can think of a different approach you'd use. But I can't think of a good way to model an inherently bi-directional relationship using a traditional relational database.
Some workarounds might be to use a View that joins the two results, or to use triggers to make sure that every mapping from A to B has a corresponding mapping from B to A, so that both of the properties always return the same objects.
If you have an instance of an Item, call it item, then the following will give you the related items...
item.RelatedItems.Select(ri => ri.Item);
Your RelatedItems property on item (ie the first navigation property you mentioned) will be a collection of RelatedItem objects, each of which has two navigation properties of its own, one of which will be named Item and will be a link to the related item.
Note that this is air code, as I'm not in front of anything I can test this on right now, but I think this will do what you want.
If you want to make it simpler, you can write an extension method to wrap up the Select(), something like this...
public static IEnumerable<Item> RelItems(this Item item) {
return item.RelatedItems.Select(ri => ri.Item);
}
Then you could just do...
item.RelItems();
Note that I couldn't name the extension method RelatedItems, as that would clash with the navigation property that EF would have created for the second table. That's perhaps not a good name for that tables, as it's not the actual items, rather the IDs of the items. Either way, the above code should work.

Subfield values in .NET Local Report

I'm attempting to use business objects as a datasource for an ASP.NET Microsoft rdlc Report and I am having problems displaying the values of subobjects in the report.
For example, if have the following two classes 'Customer' and 'Address'.
Customer
FirstName
LastName
Address
etc.
Address
HomeAddress1
etc.
Customer contains an instance of Address. If I set a list of Customers as the report datasource, I can refer to the values of each customer in the report as follows:
=Fields!FirstName.Value
However, I can't work out how to refer to the values of the 'Address' sub-object. I had assumed one of the following would work:
=Fields!Address.HomeAddress1.Value
or
=Fields!Address!HomeAddress1.Value
But neither of these do. Can anyone advise?
I had the exact same problem, and I'm sorry to say that I haven't found a way to reference sub-properties (I do hope that someone else has one though!)
What I ended up doing is creating a wrapper class that has all the properties I need directly in it.
The following syntax seems to work.
=Fields!Address.Value.HomeAddress1