In RavenDB
I need to get the latest insert for a document based on it's ID and filter by IDs from a list
ie:
List<Entity> GetLastByIds(List<int> ids);
The Entity is similar to:
class Entity
{
int id; //Unique identifier for the category the price applies to.
int Price; //Changes with time
DateTime Timestamp; //DateTime.UtcNow
}
so if I insert the following:
session.Store(new Entity{Id = 1, Price = 12.5});
session.Store(new Entity{Id = 1, Price = 7.2});
session.Store(new Entity{Id = 1, Price = 10.3});
session.Store(new Entity{Id = 2, Price = 50});
session.Store(new Entity{Id = 3, Price = 34});
...
How can I get the latest price for IDs 1 and 3 ??
I have the Map/Reduce working fine, giving me the latest for each ID, it's the filtering that I am struggling with.
I'd like to do the filtering in Raven, because if there are over 1024 price-points in total for all IDs, doing filtering on the client side is useless.
Much appreciate any help I can get.
Thank you very much in advance :)
If the Id is supposed to represent the category, then you should call it CategoryId. By calling the property Id, you are picking up on Raven's convention that it should be treated as the primary key for that document. You can't save multiple versions of the same document. It will just overwrite the last version.
Assuming you've built your index correctly, you would just query it like so:
using Raven.Client.Linq;
...
var categoryIds = new[] {1, 3}; // whatever
var results = session.Query<Entity, YourIndex>()
.Where(x=> x.CategoryId.In(categoryIds));
(The .In extension method is in the Raven.Client.Linq namespace.)
Related
I am creating Order including OrderDetail. When I have a Cart consisting of many Products, I create an Order, I want each product ID to be added to the OrderDetail including the OrderID.
But currently, I only get a ProductID (OrderID) in the first loop added to the OrderDetail. When I debug, the loop still executes enough times quantity of Product in Cart but is not added to OrderDetail.
So what is the problem that I am facing here?
Repository
public bool CreateOrder(CartViewModel invoiceVM, string userId)
{
invoiceVM.Invoices.CreateAt = DateTime.Now;
_dbContext.Invoice.Add(invoiceVM.Invoices);
_dbContext.SaveChanges();
decimal orderTotal = 0;
var cartItems = GetCartItem(userId);
foreach (var item in cartItems)
{
var invoiceDetail = new InvoiceDetails
{
ProductId = item.Products.Id,
InvoiceId = invoiceVM.Invoices.Id,
Price = item.Products.Price * item.Quantity,
Quantity = item.Quantity,
};
orderTotal += (item.Quantity * item.Products.Price);
_dbContext.InvoiceDetails.Add(invoiceDetail);
}
invoiceVM.Invoices.OrderTotal = orderTotal;
_dbContext.SaveChanges();
return true;
}
"but is not added to OrderDetail" You mean that the Order is created in your database, But you can't see any OrderDetail in your database ?
if
_dbContext.InvoiceDetails.Add(invoiceDetail);
.
.
_dbContext.SaveChanges();
are successfully pass with no errors, It save data in your database and I think it's your CartViewModel that is not updating.
you can add your data to CartViewModel in you loop or run another GetInvoice() from your dbContext.
Really stuck with Linq to SQL grouping and summing, have searched everywhere but I don't understand enough to apply other solutions to my own.
I have a view in my database called view_ProjectTimeSummary, this has the following fields:
string_UserDescription
string_ProjectDescription
datetime_Date
double_Hours
I have a method which accepts a to and from date parameter and first creates this List<>:
List<view_UserTimeSummary> view_UserTimeSummaryToReturn =
(from linqtable_UserTimeSummaryView
in datacontext_UserTimeSummary.GetTable<view_UserTimeSummary>()
where linqtable_UserTimeSummaryView.datetime_Week <= datetime_To
&& linqtable_UserTimeSummaryView.datetime_Week >= datetime_From
select linqtable_UserTimeSummaryView).ToList<view_UserTimeSummary>();
Before returning the List (to be used as a datasource for a datagridview) I filter the string_UserDescription field using a parameter of the same name:
if (string_UserDescription != "")
{
view_UserTimeSummaryToReturn =
(from c in view_UserTimeSummaryToReturn
where c.string_UserDescription == string_UserDescription
select c).ToList<view_UserTimeSummary>();
}
return view_UserTimeSummaryToReturn;
How do I manipulate the resulting List<> to show the sum of the field double_Hours for that user and project between the to and from date parameters (and not separate entries for each date)?
e.g. a List<> with the following fields:
string_UserDescription
string_ProjectDescription
double_SumOfHoursBetweenToAndFromDate
Am I right that this would mean I would have to return a different type of List<> (since it has less fields than the view_UserTimeSummary)?
I have read that to get the sum it's something like 'group / by / into b' but don't understand how this syntax works from looking at other solutions... Can someone please help me?
Thanks
Steve
Start out by defining a class to hold the result:
public class GroupedRow
{
public string UserDescription {get;set;}
public string ProjectDescription {get;set;}
public double SumOfHoursBetweenToAndFromDate {get;set;}
}
Since you've already applied filtering, the only thing left to do is group.
List<GroupedRow> result =
(
from row in source
group row by new { row.UserDescription, row.ProjectDescription } into g
select new GroupedRow()
{
UserDescription = g.Key.UserDescription,
ProjectDescription = g.Key.ProjectDescription,
SumOfHoursBetweenToAndFromDate = g.Sum(x => x.Hours)
}
).ToList();
(or the other syntax)
List<GroupedRow> result = source
.GroupBy(row => new {row.UserDescription, row.ProjectDescription })
.Select(g => new GroupedRow()
{
UserDescription = g.Key.UserDescription,
ProjectDescription = g.Key.ProjectDescription,
SumOfHoursBetweenToAndFromDate = g.Sum(x => x.Hours)
})
.ToList();
i have alot of tables with alot of columns and want to generate xml using linq without having to specify
the column names. here's a quick example:
users
---------------
user_id
name
email
user_addresses
---------------
address_id
user_id
city
state
this is the xml i want to generate with linq would look like
<user>
<name>john</name>
<email>john#dlsjkf.com</email>
<address>
<city>charleston</city>
<state>sc</state>
</address>
<address>
<city>charlotte</city>
<state>nc</state>
</address>
</user>
so i'm guessing the code would look something like this:
var userxml = new XElement("user",
from row in dc.Users where user.id == 5
select (what do i put here??)
);
i can do this for one table but can't figure out how to generate the xml for a linked table (like user_addresses).
any ideas?
ok found a way to get the xml i want, but i have to specify the related table names in the query...which is good enough for now i guess. here's the code:
XElement root = new XElement("root",
from row in dc.users
where row.user_id == 5
select new XElement("user",
row.AsXElements(),
new XElement("addresses",
from row2 in dc.user_addresses
where row2.user_id == 5
select new XElement("address", row2.AsXElements())
)
)
);
// used to generate xml tags/elements named after the table column names
public static IEnumerable<XElement> AsXElements(this object source)
{
if (source == null) throw new ArgumentNullException("source");
foreach (System.Reflection.PropertyInfo prop in source.GetType().GetProperties())
{
object value = prop.GetValue(source, null);
if (value != null)
{
bool isColumn = false;
foreach (object obj in prop.GetCustomAttributes(true))
{
System.Data.Linq.Mapping.ColumnAttribute attribute = obj as System.Data.Linq.Mapping.ColumnAttribute;
if (attribute != null)
{
isColumn = true;
break;
}
}
if (isColumn)
{
yield return new XElement(prop.Name, value);
}
}
}
}
You need to use a join. Here's one way:
var query = from user in dc.Users
from addr in dc.UserAddress
where user.Id == addr.UserId
select new XElement("user",
new XElement("name", user.Name),
new XElement("email", user.Email),
new XElement("address",
new XElement("city", addr.City),
new XElement("state", addr.State)));
foreach (var item in query)
Console.WriteLine(item);
i have alot of tables with alot of
columns and want to generate xml using
linq without having to specify the
column names.
Not quite sure how you want to achieve that. You need to state the column names that go into the XML. Even if you were to reflect over the field names, how would you filter the undesired fields out and structure them properly without specifying the column names? For example how would you setup the address part? You could get the fields by using this on your User and UserAddress classes: User.GetType().GetFields() and go through the Name of each field, but then what?
I've got two form fields from which the user submits a 'category' and an 'item'.
The following code inserts the category fine (I modified it from the WebMatrix intro PDF) but I've no idea how to then insert the 'item' into the Items table. I'll also need to add the Id of the new category to the new item row.
This is the code that's working so far
#{ var db = Database.OpenFile("StarterSite.sdf");
var Category = Request["Category"]; //was name
var Item = Request["Item"]; //was description
if (IsPost) {
// Read product name.
Category = Request["Category"];
if (Category.IsEmpty()) {
Validation.AddFieldError("Category", "Category is required");
}
// Read product description.
Item = Request["Item"];
if (Item.IsEmpty()) {
Validation.AddFieldError("Item",
"Item type is required.");
}
// Define the insert query. The values to assign to the
// columns in the Products table are defined as parameters
// with the VALUES keyword.
if(Validation.Success) {
var insertQuery = "INSERT INTO Category (CategoryName) " +
"VALUES (#0)";
db.Execute(insertQuery, Category);
// Display the page that lists products.
Response.Redirect(#Href("~/success"));
}
}
}
I'm guessing/hoping this is a very easy question to answer so hopefully there isn't much more detail required - but please let me know if there is. Thanks.
There's a Database.GetLastInsertId method within WebMatrix which returns the id of the last inserted record (assuming it's an IDENTITY column you are using). Use that:
db.Execute(insertQuery, Category);
var id = (int)db.GetLastInsertId(); //id is the new CategoryId
db.Execute(secondInsertQuery, param1, id);
I have below a collection of rows and each row consists of productid, unitid, countryid.
I need to find the details for each row in the corresponding tables (products, units, country)
for product - select product name, updatedby
for unitid - select unit name , updatedby
for countryid - select countryname, uploadby
and returning the rows which has the same format
Id = product id or unitid or countryid
name = proudct name or unit name or countryname
modified = product updatedby or unit updated by or country uploadby
So, in summary -
1. For a Collection of rows
a. use the id to get the extra details from the respective table
b. return the same type of collection for the results
2. do step 1 for
2.a For RegularToys (Run this logic on TableBigA)
2.b For CustomToys(Run this logic on TableB)
3. Return all the rows
by adding 2.a and 2.b
How to write an sql/linq query for this? thanks
If I'm understanding correctly, you want to use a given ID to find either a product, a unit or a country but you're not sure which. If that's the case, then you can build out deferred queries like this to find the given entity:
var prod = from p in db.Products
where p.ProductId = id
select new { Id = p.ProductId, Name = p.ProductName, Modified = p.UpdatedBy };
var unit = from u in db.Units
where p.UnitId = id
select new { Id = u.UnitId, Name = u.UnitName, Modified = p.UpdatedBy };
var ctry = from c in db.Countries
where c.CountryId = id
select new { Id = c.CountryId, Name = c.CountryName, Modified = c.UploadBy };
And then execute the queries until you find an entity that matches (with ?? being the null-coalesce operator that returns the right value if the left result is null).
var res = prod.SingleOrDefault() ??
unit.SingleOrDefault() ??
ctry.SingleOrDefault() ??
new { Id = id, Name = null, Modifed = null };
Without any further details I can't be more specific about the condition below, but I think you are asking for something along these lines. I'm assuming your Id's are int's (but this can be easily changed if not) and you already have an Entity Data Model for the tables you describe.
Create a class for your common data:
class RowDetail
{
public int Id { get; set; }
public string Name { get; set; }
public string Modified { get; set; }
}
Pull the information out of each of the sub tables into a new record:
IEnumerable<RowDetail> products =
from p in db.Products
where <<CONDITION>>
select
new RowDetail()
{
Id = p.ProductId,
Name = p.ProductName,
Modified = p.UpdatedBy
};
IEnumerable<RowDetail> units =
from u in db.Units
where <<CONDITION>>
select
new RowDetail()
{
Id = u.UnitId,
Name = u.UnitName,
Modified = u.UpdatedBy
};
IEnumerable<RowDetail> countries =
from c in db.Countries
where <<CONDITION>>
select
new RowDetail()
{
Id = c.CountryId,
Name = c.CountryName,
Modified = c.UploadBy
};
Finally pull all the records together in a single collection:
IEnumerable<RowDetail> results = products.Union(units).Union(countries);
I'm not sure if this is exactly what you are looking for, so feel free to give feedback and/or more details if further assistance is required.