I'm trying to select information from multiple tables via Linq. The query works if I take out the last Api query from apis in Database.PluginApis where apis.PluginId == tenantPlugin.PluginId. If I put the query back in, it results in an error System.Collections.Generic.KeyNotFoundException: The given key 'Name' was not present in the dictionary. Anyone able to see what I am doing wrong?
var results = (from tenantPlugin in Database.TenantPlugins
where tenantPlugin.TenantId == tenantId
select new TenantPlugin
{
PluginId = tenantPlugin.PluginId,
IsEnabled = tenantPlugin.IsEnabled,
TenantId = tenantPlugin.TenantId,
TenantPluginId = tenantPlugin.TenantPluginId,
Plugin = (from plugin in Database.Plugins
where plugin.PluginId == tenantPlugin.PluginId
select new Plugin
{
PluginId = plugin.PluginId,
Name = plugin.Name,
Description = plugin.Description,
ImagePath = plugin.ImagePath,
IsActive = plugin.IsActive,
Apis = (from apis in Database.PluginApis
where apis.PluginId == tenantPlugin.PluginId
select new PluginApi
{
Name = apis.Name
}).ToList<PluginApi>()
}).FirstOrDefault<Plugin>()
});
return results.ToList();
It's seems you have a perfect case to use Include() method. Try:
var results = Database.TenantPlugins
.Include(t => t.Plugin.Select(p => p.Apis))
.Where(t => t.TenantId == tenantId);
Related
I am less experienced with Lambda expression for .NET and trying to get data from SQL using lambda expression. With below query, I am able to get data back, but do not want to use include to get all properties from other tables.
public IEnumerable<ResourceGroup> GetAllServersByApplication(string application_name, string environment_name, string status)
{
var query = _context.ResourceGroup
.Include(a => a.Application)
.Include(t => t.Type)
.Include(e => e.ServersGroup).ThenInclude(e => e.Environment)
.Include(s => s.ServersGroup).ThenInclude(s => s.Server)
.Include(s => s.ServersGroup).ThenInclude(s => s.Server).ThenInclude(s => s.Status)
.Where(a => a.Application.Name == application_name && a.ServersGroup.Any(s => s.Environment.Name == environment_name && s.Server.Status.Name == status))
.ToList();
return query;
}
Lets take an example of below include statement.
.Include(s => s.ServersGroup).ThenInclude(s => s.Server)
From s.Server, I only want to select Id,ServerName,Status, and IPAddress. These are the properties from Servers class that I created as a model.
What is the easy way to exclude all the includes and only show properties that I am interested in?
Here are my tables and its properties:
Status table:
Id, Name
Application table:
Id, Name
Servers table:
Id, ServerName, Status
Environments table:
Id, Name
ResourceGroup table:
Id, Name, Application_Id, Environment_Id
ServersResourceGroup table:
Id, Server_Id, Resource_Id
UPDATE 1:
var query = _context.ResourceGroup
.SelectMany(rg => rg.ServersGroup
.Select(sg => new
{
ResourceName = rg.Name,
ApplicationName = rg.Application.Name,
ServerName = sg.Server.ServerName,
EnvironmentName = sg.Environment.Name,
Status = sg.Server.Status.Name
})).Where(a => a.ApplicationName == application_name && a.EnvironmentName == environment_name && a.Status == status).ToList();
return query;
And error from red line on query variable:
UPDATE 2:
Here is the query syntax:
var query = from rg in _context.ResourceGroup
let app = rg.Application
from sg in rg.ServersGroup
let env = sg.Environment
let srv = sg.Server
let stat = srv.Status
where app.Name == application_name
&& rg.ServersGroup.Any(s => s.Environment.Name == environment_name
&& s.Server.Status.Name == status)
select new
{
ResourceGroupName = rg.Name,
ApplicationName = app.Name,
ServerName = srv.ServerName,
Alias = srv.Alias,
IPAddress = srv.IPAddress,
Type = rg.Type.Name,
Status = stat.Name
};
return query;
Here is the red line error I get in query variable:
Your help is really appreciated. :)
Thanks,
Ray
With lambda expressions, you can use SelectMany to flatten 1-n associations into a 1 dimensional list (i.e. parent and child properties side-by-side). In your case, judging from the Where clause, I think only ResourceGroup - ServerGroup is 1 - n, so it should be something like:
var query = _context.ResourceGroup
.SelectMany
(
rg => rg.ServersGroup
.Select(sg => new
{
ResourceGroup = rg.Name,
Application = rg.Application.Name,
Server = sg.Server.ServerName,
// etc.
})
)
Of course it's good to know how to use lambda expressions, but there's really no point in using them when query syntax makes for much better comprehensible code.
The equivalent in query syntax is:
var query = from rg in _context.ResourceGroup
let app = rg.Application
from sg in rg.ServersGroup
let env = sg.Environment
let srv = sg.Server
let stat = srv.Status
where app.Name == application_name
&& sg.ServersGroup.Any(s => s.Environment.Name == environment_name
&& s.Server.Status.Name == status)
select new
{
ResourceGroup = rg.Name,
Application = app.Name,
Server = srv.ServerName,
// etc. use any property from rg, app, sg, srv, stat
};
As you see -
n - 1 associations are represented by a let statement (which really only helps here to shorten the references in the select)
1-n associations are represented by the from ... from syntax, which is query syntax for SelectMany.
I didn't change the Where clause in the query syntax. Maybe you can use ...
where app.Name == application_name
&& env.Name == environment_name
&& stat.Name == status)
... but note that this is different. The original where returns all ResourceGroup having at least one ServerGroup meeting the condition (and maybe other groups with different environments and statuses). The other where only returns data with environments and statuses equal to the search parameters.
Don't Include all the related tables, but Select all the fields you need. You might find it easier to make a new class to hold the data.
Sorry if I can't make a real query statement here, but your question doens't specify the fields you need.
I've got a table Installation which can contains one or many Equipements.
And for functionnal reasons, I've overwritten my table Installation and added a field NbrEquipements.
I want to fill this field with Linq, but I'm stuck...
Due to special reasons, there is no relation between these to tables. So, no Installation.Equipements member into my class. Therefore, no Installation.Equipements.Count...
I'm trying some stuff. Here is my code:
var query = RepoInstallation.AsQueryable();
// Some filter
query = query.Where(i => i.City.RegionId == pRegionId));
int?[] etatIds = { 2, 3 };
query = (from i in query
select new Installation
{
NbrEquipements= (from e in RepoEquipement.AsQueryable()
where e.InstallationSpecialId == i.SpecialId
&& (etatIds.Contains(e.EquEtat))
select e.SasId
).Count()
});
But with this try, I got this error:
The entity or complex type 'myModel.Installation' cannot be constructed in a LINQ to Entities query
I've tried some other stuff but I'm always turning around...
Another thing that can be useful for me: It would be great to fill a field called Equipements which is a List<Equipement>.
After that, I would be able to Count this list...
Is it possible ?
Tell me if I'm not clear.
Thanks in advance.
Here is the final code:
//In the class:
[Dependency]
public MyEntities MyEntities { get; set; }
//My Methode code:
var query = MyEntities .SasInstallations.AsQueryable();
// Some filter
query = query.Where(i => i.City.RegionId == pRegionId));
var liste = new List<Installation>();
var queryWithListEquipements =
from i in query
select new
{
Ins = i,
EquipementsTemp = (from eq in MyEntities.Equipements.AsQueryable()
where eq.SpecialId == i.SpecialId
&& (etatIds.Contains(eq.SasEquEtat))
select eq
).ToList()
};
var listWithListEquipements = queryWithListEquipements.ToList();
foreach (var anonymousItem in listWithListEquipements)
{
var ins = anonymousItem.Ins;
ins.Equipements = anonymousItem.EquipementsTemp;
ins.NumberEquipements = ins.Equipements.Count();
liste.Add(ins);
}
return liste;
By the way, this is very very fast (even the listing of Equipements). So this is working exactly has I wished. Thanks again for your help everyone!
Use an anonymous type. EF does not like to instantiate entity classes inside a query.
var results = (from i in query
select new
{
NbrEquipements= (from e in RepoEquipement
where e.InstallationSpecialId == i.SpecialId
&& (etatIds.Contains(e.EquEtat))
select e.SasId
).Count()
})
.ToList();
Notice how I used select new instead of select new Installation.
You can then use the data inside the list (which is now in memory) to create instances of type Installation if you want like this:
var installations = results.Select(x =>
new Installation
{
NbrEquipements = x.NbrEquipements
}).ToList();
Here is how to obtain the list of equipment for each installation entity:
var results = (from i in query
select new
{
Installation = i,
Equipment = (from e in RepoEquipement
where e.InstallationSpecialId == i.SpecialId
&& (etatIds.Contains(e.EquEtat))
select e).ToList()
})
.ToList();
This will return a list of anonymous objects. Each object will contain a property called Installation and another property called Equipment (which is a list). You can easily convert this list (of anonymous objects) to another list of whatever type that you want.
I have a two linq query that returns type of IEnumerable. First query returns filtered values and second query return all values I want to except from second query to first query like minus operator in SQL and bind to my listboxs.
my code sample =>
using (ISession session = SessionManager.CurrentSession)
{
IEnumerable<RoleDefinition> roleAssigned = from groupRole in session.Query<GroupRole>()
join roleDef in session.Query<RoleDefinition>() on groupRole.RoleDefinitionId equals
roleDef.RoleDefinitionId
where groupRole.GroupId == SelectedGroupId
orderby roleDef.RoleName
select new RoleDefinition
{
RoleName = roleDef.RoleName
};
IEnumerable<RoleDefinition> roleUnassigned = from grole in session.Query<RoleDefinition>()
orderby grole.RoleName
select new RoleDefinition
{
RoleName = grole.RoleName
};
List<RoleDefinition> lRoleAss = roleAssigned.ToList();
List<RoleDefinition> lRoleUnAss = roleUnassigned.ToList();
lRoleUnAss = lRoleUnAss.Where(x => !lRoleAss.Contains(x)).ToList();
lsbAssigned.DataSource = lRoleAss;
lsbAssigned.TextField = "RoleName";
lsbAssigned.ValueField = "RoleName";
lsbAssigned.DataBind();
lsbUnAssigned.DataSource = lRoleUnAss;
lsbUnAssigned.TextField = "RoleName";
lsbUnAssigned.ValueField = "RoleName";
lsbUnAssigned.DataBind();
}
EDIT => I fixed my code as below and my function works successfully
List<RoleDefiniton> filteredUnassign = lRoleUnAss.Where(def => !lRoleAss.Select(x => x.RoleName).Contains(def.RoleName)).ToList();
Change the following line:
lRoleUnAss = lRoleUnAss.Where(x => !lRoleAss.Contains(x)).ToList();
To
var results = lRoleUnAss.Except(lRoleAss).ToList();
and use results to get the final list.
I declared a new variable because i do not know if you want to keep the initial list intact or not. If you do not mind changing it you may try:
lRoleUnAss = lRoleUnAss.Except(lRoleAss).ToList();
I am wondering if there is a better, more efficient way to re-code the linq syntax below to make the query run faster i.e. with a single call to the database. My database is located remotely which causes this to be quite slow:
var query = (from ticket in dataClassesDataContext.Tickets.Where(TicketsToShow.And(SearchVals))
select new
{
Priority = ticket.TicketPriority.TicketPriorityName,
Ticket = string.Format(TicketFormat, ticket.TicketID),
AssetId = ticket.Asset.Serial,
OpenDate = ticket.CheckedInDate,
OpenFor = CalculateOpenDaysAndHours(ticket.CheckedInDate, ticket.ClosedDate),
Account = ticket.Account.Customer.Name,
Description = ticket.Description.Replace("\n", ", "),
Status = ticket.TicketStatus.TicketStatusName,
Closed = ticket.ClosedDate,
THIS IS THE CAUSE ====>>> Amount = GetOutstandingBalanceForTicket(ticket.TicketID),
Paid = ticket.Paid,
Warranty = ticket.WarrantyRepair,
AssetLocation = GetAssetLocationNameFromID(ticket.Asset.LocationID, AssLocNames)
}).Skip(totalToDisplay * page).Take(totalToDisplay);
if (SortOrder.ToLower().Contains("Asc".ToLower()))
{
query = query.OrderBy(p => p.OpenDate);
}
else
{
query = query.OrderByDescending(p => p.OpenDate);
}//ENDIF
The main cause for the poor performance is the code in the function GetOutstandingBalanceForTicket below which calculates the sum of all items in an invoice and returns this as a total in a string:
public static string GetOutstandingBalanceForTicket(int TicketID)
{
string result = string.Empty;
decimal total = 0;
try
{
using (DataClassesDataContext dataClassesDataContext = new DataClassesDataContext(cDbConnection.GetConnectionString()))
{
var queryCustomerTickets = from ticket in dataClassesDataContext.Tickets
where
(ticket.TicketID == TicketID)
select ticket;
if (queryCustomerTickets != null)
{
foreach (var ticket in queryCustomerTickets)
{
var queryTicketChargeItems = from chargeItem in dataClassesDataContext.ProductChargeItems
where chargeItem.ChargeID == ticket.ChargeID &&
chargeItem.Deleted == null
select chargeItem;
foreach (var chargeItem in queryTicketChargeItems)
{
total += (chargeItem.Qty * chargeItem.Price);
}
}
}
}
}
catch (Exception ex)
{
}
return total.ToString("0.##");
}
Thank you in advance.
As you pointed out this code is quite slow as a query will be required for each ticket.
to eliminate the need for multiple queries you should look at applying an inner join between the ticketsToShow and the tickets entity (on the ticketid), using groupby to provide the sum of the charges for each ticket.
This is well illustrated in the answers to LINQ: Using INNER JOIN, Group and SUM
Ideally you would probably approach it more as an eager loading all at once type of setup. However, I do not think linq2sql supports that (I know EF does). One thing you can do is avoid the nested query though. Since you already have access to the ticket table, perhaps you should just issue a Sum() on it from your select statement. Hard for me to verify if any of this is an improvement so this code is kind of on the fly if you will.
//(from ticket in dataClassesDataContext.Tickets.Where(TicketsToShow.And(SearchVals))
(from ticket in dataClassesDataContext.Tickets
//this would be where you could eager load if possible (not entirely required)
//.Include is an EF method used only as example
/*.Include(t => t.TicketPriority)//eager load required entities
.Include(t => t.Asset)//eager load required entities
.Include(t => t.Account.Customer)//eager load required entities
.Include(t => t.TicketStatus)//eager load required entities
.Include(t => t.ProductChargeItems)//eager load required entities
*/
.Where(TicketsToShow.And(SearchVals))
select new
{
Priority = ticket.TicketPriority.TicketPriorityName,
Ticket = string.Format(TicketFormat, ticket.TicketID),
AssetId = ticket.Asset.Serial,
OpenDate = ticket.CheckedInDate,
OpenFor = CalculateOpenDaysAndHours(ticket.CheckedInDate, ticket.ClosedDate),
Account = ticket.Account.Customer.Name,
Description = ticket.Description.Replace("\n", ", "),
Status = ticket.TicketStatus.TicketStatusName,
Closed = ticket.ClosedDate,
//Use Sum and the foreign relation instead of a nested query
Amount = ticket.ProductChargeItems.Where(pci => pci.Deleted == null).Sum(pci => pci.Qty * pci.Price),
Paid = ticket.Paid,
Warranty = ticket.WarrantyRepair,
AssetLocation = GetAssetLocationNameFromID(ticket.Asset.LocationID, AssLocNames)
}).Skip(totalToDisplay * page).Take(totalToDisplay);
if (SortOrder.ToLower().Contains("Asc".ToLower()))
{
query = query.OrderBy(p => p.OpenDate);
}
else
{
query = query.OrderByDescending(p => p.OpenDate);
}
I think, you can make this query simplier. Somethink like this:
public static string GetOutstandingBalanceForTicket(DataClassesDataContext context, int TicketID)
{
decimal total = 0;
var total = (from ticket in context.Tickets
join chargeItem from context.ProductChargeItems on chargeItem.ChargeID == ticket.ChargeID
where (ticket.TicketID == TicketID && chargeItem.Deleted == null)
select chargeItem).Sum(chargeItem => chargeItem.Qty * chargeItem.Price);
return total.ToString("0.##");
}
/*...*/
Amount = GetOutstandingBalanceForTicket(dataClassesDataContext, ticket.TicketID),
Now, you can inline this methos in your query.
It can contains syntax errors, because I wrote it in notepad.
I have the following code. The function has a lot of Linq calls and I had help on putting this into place.
public IList<Content.Grid> Details(string pk)
{
IEnumerable<Content.Grid> details = null;
IList<Content.Grid> detailsList = null;
var data = _contentRepository.GetPk(pk);
var refType = this.GetRefType(pk);
var refStat = this.GetRefStat(pk);
var type = _referenceRepository.GetPk(refType);
var stat = _referenceRepository.GetPk(refStat);
details =
from d in data
join s in stat on d.Status equals s.RowKey into statuses
from s in statuses.DefaultIfEmpty()
join t in type on d.Type equals t.RowKey into types
from t in types.DefaultIfEmpty()
select new Content.Grid
{
PartitionKey = d.PartitionKey,
RowKey = d.RowKey,
Order = d.Order,
Title = d.Title,
Status = s == null ? null : s.Value,
StatusKey = d.Status,
Type = t == null ? null : t.Value,
TypeKey = d.Type,
Link = d.Link,
Notes = d.Notes,
TextLength = d.TextLength
};
detailsList = details
.OrderBy(item => item.Order)
.ThenBy(item => item.Title)
.Select((t, index) => new Content.Grid()
{
PartitionKey = t.PartitionKey,
RowKey = t.RowKey,
Row = index + 1,
Order = t.Order,
Title = t.Title,
Status = t.Status,
StatusKey = t.StatusKey,
Type = t.Type,
TypeKey = t.TypeKey,
Link = t.Link,
Notes = t.Notes,
TextLength = t.TextLength,
})
.ToList();
return detailsList;
}
The first uses one format for Linq and the second another. Is there some way that I could simplify and/or combine these? I would really like to make this code simpler but I am not sure how to do this. Any suggestions would be much appreciated.
Of course you can combine them. The Linq keywords such as from, where and select get translated into calls like the Extension methods that you call below, so effectively there's no difference.
If you really want to combine them, the quickest way is to put () around the first query, then append the method calls you use on details in the second query. Like this:
detailsList =
(from d in data // <-- The first query
// ...
select new Content.Grid
{
// ...
})
.OrderBy(item => item.Order) // <-- The calls from the second query
.ThenBy(item => item.Title)
.Select((t, index) => new Content.Grid()
{
//...
}).ToList();
But i think that would be ugly. Two queries are just fine IMO.