I am a beginner in MongoDB. Please see my models below.
public class Technology
{
public Technology()
{
ProductGroups = new List<ProductGroup>();
}
[BsonRepresentation(BsonType.ObjectId)]
public ObjectId _id { get; set; }
public string Name { get; set; }
public IEnumerable<ProductGroup> ProductGroups { get; set; }
}
public class ProductGroup
{
[BsonRepresentation(BsonType.ObjectId)]
public ObjectId _id { get; set; }
public string Name { get; set; }
}
Now the data shows like below.
I am try to add the ProductGroup ( it's a BsonDocument Collection) collection in Technology.
Use generic types where you can. Because this code parent["ProductGroups"] is dangerous place for any refactoring.
Your task can be done in one query
var productGroup = new ProductGroup { Id = ObjectId.GenerateNewId(), Name = model.Name };
var collection = database.GetCollection<Technology>("Technology");
var update = Builders<Technology>.Update.AddToSet(x => x.ProductGroups, productGroup);
await collection.FindOneAndUpdateAsync(x => x.Id == model._id, update);
Change your Model of Technology as
[BsonElementAttribute("productgroups")]
public IList<ProductGroup> ProductGroups{ get; set; }
Then,
var productGroup = new BsonDocument().Add("_id", productGroup_id).Add("Name", name);
var technologies = database.GetCollection("technology");
var technology = technologies.FindOneById(ObjectId.Parse(technology_id));
technology["productgroups"] = new BsonArray().Add(BsonValue.Create(productGroup));
technologies.Save(technology);
#CodingDefined I change my code as per the v2.0.1.27
Please see my code below. Thank you very much for your help.
var productGroup = new BsonDocument()
.Add("_id", ObjectId.GenerateNewId())
.Add("Name", model.Name);
BsonDocument parent = null;
var _parent = Collection.FindOneByIdAs(typeof(BsonDocument), model._id);
if (_parent != null)
{
parent = _parent.ToBsonDocument();
parent["ProductGroups"] = new BsonArray().Add(BsonValue.Create(productGroup));
Collection.Save(parent);
}
Please make sure, the new child record is not clearing the existing records
parent["ProductGroups"] = parent["ProductGroups"].AsBsonArray.Add(productGroup);
Related
I Create a web-site and I have a problem. When I'm tring to get datas from mongodb and convert it to list, I have an error "Cannot apply indexing with [] to an expression of type 'CategoryModel'"
this is classes
public class CategoryModel
{
[BsonId]
public ObjectId id { get; set; }
[BsonElement("title")]
[JsonProperty("title")]
public string Name { get; set; }
[BsonElement("slug")]
public string slug { get; set; }
[BsonElement("__v")]
public int __v { get; set; }
}
public class ProductsModel
{
[BsonId]
public ObjectId id { get; set; }
[BsonElement("title")]
public string Name { get; set; }
[BsonElement("desc")]
public string Desc { get; set; }
[BsonElement("price")]
public int price { get; set; }
[BsonElement("category")]
public CategoryModel category { get; set; }
[BsonElement("image")]
public string ImageURL { get; set; }
}
this is my conntroller
public class ProductsController:Controller
{
private readonly IConfiguration _configuration;
List<CategoryModel> categoriesList = new List<CategoryModel>();
List<ProductsModel> productsList = new List<ProductsModel>();
[HttpGet("products")]
public async Task<IActionResult> Product()
{
var client = new MongoClient("mongodb://localhost:27017/");
var database = client.GetDatabase("cmscart");
var collection = database.GetCollection<CategoryModel>("categories");
var result = await collection.Find(new BsonDocument()).ToListAsync();
foreach (var item in result)
{
categoriesList.Add(new CategoryModel() { Name = (string)item["[title]"] }); //here I have an error
}
//products
var client2 = new MongoClient("mongodb://localhost:27017");
var database2 = client2.GetDatabase("cmscart");
var collection2 = database2.GetCollection<ProductsModel>("products");
var result2 = await collection2.Find(new BsonDocument()).ToListAsync();
foreach (var item2 in result2)
{
productsList.Add(new ProductsModel() { Name = (string)item2["title"], Desc = (string)item2["desc"], price = (int)item2["price"], ImageURL = (string)item2["image"] }); // and here I have an error
}
return View(categoryProduct);
}
}
I found a lot of solutions but I don't understand why this error is appear, because if this trick do with SQL then I don't have this error
You should be able to use the deserialized object directly:
var client = new MongoClient("mongodb://localhost:27017/");
var database = client.GetDatabase("cmscart");
var collection = database.GetCollection<CategoryModel>("categories");
List<CategoryModel> categoriesList = await collection.Find(new BsonDocument()).ToListAsync();
//products
var collection2 = database2.GetCollection<ProductsModel>("products");
List<ProductsModel> products = await collection2.Find(new BsonDocument()).ToListAsync();
Also, don't use class properties for local variables, declare everything in the innermost scope possible (in general). Ideally the MongoClient or Database would be injected into the class constructor too. You don't want to be instantiating them in an action method and you definitely don't want configuration values in there.
Initially I was using automapper for this but its seems way harder for me to implement it.
Basically, I just want to return an empty list instead of null values. I can do this on projects level but not on teammates level. The API must not return a null because the UI that consumes it will have an error.
Sample of my implementation below:
Projects = !Util.IsNullOrEmpty(x.Projects) ? x.Projects : new List<ProjectsDto>(),
Ill highly appreciate if someone can guide me on how to manually map this with null/empty checking.
If you can also provide and example using automapper that too will be very helpful.
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
public List<ProjectsDto> Projects { get; set; }
}
public class ProjectsDto
{
public string Status { get; set; }
public List<TeammatesDto> Teammates { get; set; }
}
public class TeammatesDto
{
public string TeammateName { get; set; }
public string PreviousProject { get; set; }
}
//Get by Id
var employee = await _context.Employees
.Where(x => x.id.Equals(request.Id)
.FirstOrDefaultAsync(cancellationToken);
//Map employee
EmployeeDto ret = new EmployeeDto()
{
Id = employee.id,
Name = employee.Name,
Projects = null //TODO: map manually
}
//Get all employees
var employees = await _context.Employees.AsNoTracking()
.ToListAsync(cancellationToken);
//Map here
IList<EmployeeDto> list = new List<EmployeeDto>();
foreach (var x in employees)
{
EmployeeDto dto = new EmployeeDto()
{
Id = x.id,
Name = x.Name,
Projects = null //TODO: map manually
};
list.Add(dto);
}
return list;
Instead of materializing full entities, do the following:
var query = _context.Employees
.Select(e = new EmployeeDto
{
Id = e.id,
Name = e.Name,
Projects = e.Projects.Select(p => new ProjectDto
{
Status = p.Status,
Templates = p.Templates.Select(t => new TemplateDto
{
TeammateName = t.TeammateName,
PreviousProject = t.PreviousProject
}).ToList()
}).ToList()
}
);
var result = await query.ToListAsync();
How can i make filter and add/update third, fourth level child of a mongodb document using C#.
I can add/Update till second level but not further. Please provide me a solution or any kind reference from where can get help. Is there any other way to do it except builders..Elemmatch.
Here is my classes and code:
namespace CrudWithMultilvelNestedDoc
{
public class Channel
{
[BsonId]
[BsonRepresentation(BsonType.String)]
public string Id { get; set; }
public string Name { get; set; }
public Episode[] Episodes { get; set; }
}
public class Episode
{
[BsonId]
[BsonRepresentation(BsonType.String)]
public string Id { get; set; }
public string Name { get; set; }
public Track[] Tracks { get; set; }
}
public class Track
{
[BsonId]
[BsonRepresentation(BsonType.String)]
public string Id { get; set; }
public string Name { get; set; }
public Like[] Likes { get; set; }
}
public class Like
{
[BsonId]
[BsonRepresentation(BsonType.String)]
public string Id { get; set; }
public string Name { get; set; }
}
}
//First Method
//var filter = Builders<Channel>.Filter.And(Builders<Channel>
// .Filter.Where(x => x.Id == "5e4606e6ae7b090688671416"), // OR &
// Builders<Channel>.Filter.ElemMatch(e => e.Episodes, Builders<Episode>
// .Filter.Eq(e => e.Id, "5e460851d29c1b3df4d27b7d")));
//Second Method
//var filter = Builders<Channel>.Filter.Eq(e => e.Id, "5e4606e6ae7b090688671416")
// & Builders<Channel>.Filter.ElemMatch(e => e.Episodes, Builders<Episode>.Filter.Eq(e => e.Id, "5e46071d385a672b0cea0f86"));
//Third Method
var filter = channelFilter.ElemMatch(e => e.Episodes, episodeFilter.ElemMatch(e=> e.Tracks, trackFilter.Eq(e => e.Id, "5e460dbe2bc5e70c9cfeac21")));
var data = collection.Find(filter);
//Update Filter
var update = Builders<Channel>.Update.Push("Episodes[-1].Tracks[-1].Likes", like);
var result = collection.UpdateOne(filter, update);
//Data
{"_id":"5e4606e6ae7b090688671416","Name":"Channel 1","Episodes":[{"_id":"5e46071d385a672b0cea0f86","Name":"Episode 1","Tracks":[{"_id":"5e460dbe2bc5e70c9cfeac21","Name":"Trak 1","Likes":[]},{"_id":"5e4612d60747a2121870c815","Name":"Trak 2","Likes":[]}]},{"_id":"5e460851d29c1b3df4d27b7d","Name":"Episode 2","Tracks":[{"_id":"5e460e307ca6843758ce814e","Name":"Trak 1","Likes":[]}]}]}
As per documentation:
The positional $ operator cannot be used for queries which traverse more than one array
So using -1 is not a way forward here. The approach you should take is the $ positional filtered operator.
There's no strongly-typed representation in C# so your code can look like below:
var filter = Builders<Channel>.Filter.Eq(x => x.Id, "5e4606e6ae7b090688671416");
var like = new Like() {Name = "new like", Id = "1"};
var episodeId = "5e46071d385a672b0cea0f86";
var trackId = "5e460dbe2bc5e70c9cfeac21";
var update = Builders<Channel>.Update.Push("Episodes.$[e].Tracks.$[t].Likes", like);
var arrayFilters = new List<ArrayFilterDefinition>();
ArrayFilterDefinition<BsonDocument> episodesFilter = new BsonDocument("e._id", new BsonDocument("$eq", episodeId));
ArrayFilterDefinition<BsonDocument> tracksFilter = new BsonDocument("t._id", new BsonDocument("$eq", trackId));
arrayFilters.Add(episodesFilter);
arrayFilters.Add(tracksFilter);
var updateOptions = new UpdateOptions { ArrayFilters = arrayFilters };
var result = mongoDBCollection.UpdateOne(filter, update, updateOptions);
I have two DTOs:
public class MasterDTO
{
public int Id { get; set; }
public string Name { get; set; }
public List<DetailDTO> Details { get; set; }
}
public class DetailDTO
{
public int Id { get; set; }
public string DetailName { get; set; }
}
Also, I have a function:
using (var context = new Context())
{
var r = context.MasterData
.Select(d => new MasterDTO
{
Id = d.Id,
Name = d.Name,
}
}
I need to fill the list of DetailDTOs too and do it in a single request.
At this moment, I have to get list of DetailsData data and add it through foreach to the MasterDTO, which, of course causes a lot of requests to the database server.
Is there a better solution?
In your data call, do an eager load on your DetailData.
Example:
var r = context.MasterData.Include("DetailData")
DetailData should be the name of your navigation property attached to your MasterData entity.
This will cause detail data to be pulled along with your call for MasterData.
The full call may look something like this:
using (var context = new Context())
{
context.LazyLoadingEnabled = false;
var r = context.MasterData.Include("DetailData")
.Select(d => new MasterDTO()
{
Id = d.Id,
Name = d.Name,
Details = d.Details.Select(dt => new DetailDTO()
{
Id = dt.Id,
DetailName = dt.DetailName
})
});
}
I hope it's more clear what I want to do from the code than the title. Basically I am grouping by 2 fields and want to reduce the results into a collection all the ProductKey's constructed in the Map phase.
public class BlockResult
{
public Client.Names ClientName;
public string Block;
public IEnumerable<ProductKey> ProductKeys;
}
public Block()
{
Map = products =>
from product in products
where product.Details.Block != null
select new
{
product.ClientName,
product.Details.Block,
ProductKeys = new List<ProductKey>(new ProductKey[]{
new ProductKey{
Id = product.Id,
Url = product.Url
}
})
};
Reduce = results =>
from result in results
group result by new {result.ClientName, result.Block} into g
select new BlockResult
{
ClientName = g.Key.ClientName,
Block = g.Key.Block,
ProductKeys = g.SelectMany(x=> x.ProductKeys)
};
}
I get some weird System.InvalidOperationException and a source code dump where basically it is trying to initialize the list with an int (?).
If I try replacing the ProductKey with just IEnumerable ProductIds (and make appropriate changes in the code). Then the code runs but I don't get any results in the reduce.
You probably don't want to do this. Are you really going to need to query in this manner? If you know the context, then you should probably just do this:
var q = session.Query<Product>()
.Where(x => x.ClientName == "Joe" && x.Details.Block == "A");
But, to answer your original question, the following index will work:
public class Products_GroupedByClientNameAndBlock : AbstractIndexCreationTask<Product, Products_GroupedByClientNameAndBlock.Result>
{
public class Result
{
public string ClientName { get; set; }
public string Block { get; set; }
public IList<ProductKey> ProductKeys { get; set; }
}
public class ProductKey
{
public string Id { get; set; }
public string Url { get; set; }
}
public Products_GroupedByClientNameAndBlock()
{
Map = products =>
from product in products
where product.Details.Block != null
select new {
product.ClientName,
product.Details.Block,
ProductKeys = new[] { new { product.Id, product.Url } }
};
Reduce = results =>
from result in results
group result by new { result.ClientName, result.Block }
into g
select new {
g.Key.ClientName,
g.Key.Block,
ProductKeys = g.SelectMany(x => x.ProductKeys)
};
}
}
When replicating I get the same InvalidOperationException, stating that it doesn't understand the index definition (stack trace omitted for brevity).
Url: "/indexes/Keys/ByNameAndBlock"
System.InvalidOperationException: Could not understand query:
I'm still not entirely sure what you're attempting here, so this may not be quite what you're after, but I managed to get the following working. In short, Map/Reduce deals in anonymous objects, so strongly typing to your custom types makes no sense to Raven.
public class Keys_ByNameAndBlock : AbstractIndexCreationTask<Product, BlockResult>
{
public Keys_ByNameAndBlock()
{
Map = products =>
from product in products
where product.Block != null
select new
{
product.Name,
product.Block,
ProductIds = product.ProductKeys.Select(x => x.Id)
};
Reduce = results =>
from result in results
group result by new {result.Name, result.Block}
into g
select new
{
g.Key.Name,
g.Key.Block,
ProductIds = g.SelectMany(x => x.ProductIds)
};
}
}
public class Product
{
public Product()
{
ProductKeys = new List<ProductKey>();
}
public int ProductId { get; set; }
public string Url { get; set; }
public string Name { get; set; }
public string Block { get; set; }
public IEnumerable<ProductKey> ProductKeys { get; set; }
}
public class ProductKey
{
public int Id { get; set; }
public string Url { get; set; }
}
public class BlockResult
{
public string Name { get; set; }
public string Block { get; set; }
public int[] ProductIds { get; set; }
}