I am trying to connect to MongoDB with Web Api, trying to return the connected data in MongoDB using Get. The name of the database is "test" and the collection name is "restaurant".
Here is the code I have
public IEnumerable<restaurants> Get()
{
var client = new MongoClient();
var dbs = client.GetDatabase("test");
var collection = dbs.GetCollection<restaurants>("restaurants");
return collection;
}
The last collection word is underlined, and I have not found what needs to be returned (in place of collection) in order to show the database in MongoDB (using postman).
I think you are trying to return IMongoCollection, not IEnumerable so last line is underlined :)
Try to transform collection to List (asynchronously), then return. For example:
public Task<List<restaurants>> GetRestaurantsAsync()
{
var client = new MongoClient();
var dbs = client.GetDatabase("test");
var collection = dbs.GetCollection<restaurants>("restaurants");
return await collection.Find(_ => true).ToListAsync();
}
public async Task MainAsync()
{
List<restaurants> restaurantsList = await GetRestaurantsAsync();
}
Note: it depends on which version of mongo c# driver you're using.
I have a Profiles document collection with array of the following documents :
public class Profile2MailList
{
[BsonElement(elementName: "listId")]
[BsonRequired]
public int MailListId;
[BsonElement(elementName: "status")]
[BsonRequired]
public int Status;
[BsonElement(elementName: "subscriptionDate")]
[BsonRequired]
public DateTime SubscriptionDate;
}
in each Profile.
I need to add to the Profile2MailList array a new Profile2MailList document in each Profile based on Profile2MailList which already contains in a certain Profile. So i need to
Take needed profiles from Profiles collection
Update
Profile2Maillist array in each Profile
Run update command
How can i perform that action via C# 2.0 MongoDb Driver. I have MongoDb v 3.0.2.
I try to make it by the following way :
List<Profile> listProfiles = new List<Profile>();
foreach (Profile item in profiles)
{
item.MailLists.ToList().Add(new Profile2MailList(maillistId, item.MailLists.FirstOrDefault().Status));
var t = item;
listProfiles.Add(t);
}
dbCollection.UpdateManyAsync(listProfiles)
The method "UpdateManyAsync" only works if you want to perform one type of update, which doesn't seem to be your case. What you want to do is perform a Bulk-Update instead. Building on your example, you would want to do something like:
var bulk = new List<WriteModel<Profile>>();
foreach (Profile item in profiles)
{
var newProfile = new Profile2MailList(maillistId, item.MailLists.FirstOrDefault().Status);
var filter = Builders<Profile>.Filter.Eq(g => g.Id, item.Id);
var update = Builders<Profile>.Update.AddToSet(item.MailLists, newProfile);
var updatemodel = new UpdateOneModel<Profile>(filter, update);
bulk.Add(updatemodel);
}
await profileCollection.BulkWriteAsync(bulk);
The AddToSet operator adds a value to an array unless the value is already present.
I'm new to lucene.net. I want to implement search functionality on a client database. I have the following scenario:
Users will search for clients based on the currently selected city.
If the user wants to search for clients in another city, then he has to change the city and perform the search again.
To refine the search results we need to provide filters on Areas (multiple), Pincode, etc. In other words, I need the equivalent lucene queries to the following sql queries:
SELECT * FROM CLIENTS
WHERE CITY = N'City1'
AND (Area like N'%area1%' OR Area like N'%area2%')
SELECT * FROM CILENTS
WHERE CITY IN ('MUMBAI', 'DELHI')
AND CLIENTTYPE IN ('GOLD', 'SILVER')
Below is the code I've implemented to provide search with city as a filter:
private static IEnumerable<ClientSearchIndexItemDto> _search(string searchQuery, string city, string searchField = "")
{
// validation
if (string.IsNullOrEmpty(searchQuery.Replace("*", "").Replace("?", "")))
return new List<ClientSearchIndexItemDto>();
// set up Lucene searcher
using (var searcher = new IndexSearcher(_directory, false))
{
var hits_limit = 1000;
var analyzer = new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_30);
// search by single field
if (!string.IsNullOrEmpty(searchField))
{
var parser = new QueryParser(Lucene.Net.Util.Version.LUCENE_30, searchField, analyzer);
var query = parseQuery(searchQuery, parser);
var hits = searcher.Search(query, hits_limit).ScoreDocs;
var results = _mapLuceneToDataList(hits, searcher);
analyzer.Close();
searcher.Dispose();
return results;
}
else // search by multiple fields (ordered by RELEVANCE)
{
var parser = new MultiFieldQueryParser(Lucene.Net.Util.Version.LUCENE_30, new[]
{
"ClientId",
"ClientName",
"ClientTypeNames",
"CountryName",
"StateName",
"DistrictName",
"City",
"Area",
"Street",
"Pincode",
"ContactNumber",
"DateModified"
}, analyzer);
var query = parseQuery(searchQuery, parser);
var f = new FieldCacheTermsFilter("City",new[] { city });
var hits = searcher.Search(query, f, hits_limit, Sort.RELEVANCE).ScoreDocs;
var results = _mapLuceneToDataList(hits, searcher);
analyzer.Close();
searcher.Dispose();
return results;
}
}
}
Now I have to provide more filters on Area, Pincode, etc. in which Area is multiple. I tried BooleanQuery like below:
var cityFilter = new TermQuery(new Term("City", city));
var areasFilter = new FieldCacheTermsFilter("Area",areas); -- where type of areas is string[]
BooleanQuery filterQuery = new BooleanQuery();
filterQuery.Add(cityFilter, Occur.MUST);
filterQuery.Add(areasFilter, Occur.MUST); -- here filterQuery.Add not have an overloaded method which accepts string[]
If we perform the same operation with single area then it's working fine.
I've tried with ChainedFilter like below, which doesn't seems to satisfy the requirement. The below code performs or operation on city and areas. But the requirement is to perform OR operation between the areas provided in the given city.
var f = new ChainedFilter(new Filter[] { cityFilter, areasFilter });
Can anybody suggest to me how to achieve this in lucene.net? Your help will be appreciated.
You're looking for the BooleanFilter. Almost any query object has a matching filter object.
Look into TermsFilter (from Lucene.Net.Contrib.Queries) if your indexing doesn't match the requirements of FieldCacheTermsFilter. From the documentation of the later; "this filter requires that the field contains only a single term for all documents".
var cityFilter = new FieldCacheTermsFilter("CITY", new[] {"MUMBAI", "DELHI"});
var clientTypeFilter = new FieldCacheTermsFilter("CLIENTTYPE", new [] { "GOLD", "SILVER" });
var areaFilter = new TermsFilter();
areaFilter.AddTerm(new Term("Area", "area1"));
areaFilter.AddTerm(new Term("Area", "area2"));
var filter = new BooleanFilter();
filter.Add(new FilterClause(cityFilter, Occur.MUST));
filter.Add(new FilterClause(clientTypeFilter, Occur.MUST));
filter.Add(new FilterClause(areaFilter, Occur.MUST));
IndexSearcher searcher = null; // TODO.
Query query = null; // TODO.
Int32 hits_limit = 0; // TODO.
var hits = searcher.Search(query, filter, hits_limit, Sort.RELEVANCE).ScoreDocs;
What you are looking for is nested boolean queries so that you have an or (on your cities) but that whole group (matching the or) is itself matched as an and
filter1 AND filter2 AND filter3 AND (filtercity1 OR filtercity2 OR filtercity3)
There is already a good description of how to do this here:
How to create nested boolean query with lucene API (a AND (b OR c))?
I'm trying to use the collection.FindAndModify and give it a IMongoQuery which selects all the documents. But I can not find how to create a query without any conditions!
Can anyone tell me how to do this? I'm using MongoDB C# Driver v1.8.3.
Here's my code:
var query = ???;
var sortBy = SortBy.Ascending(new string[] { "last_update" });
var update = Update<Entity>.Set(e => e.last_update, DateTime.Now);
var fields = Fields.Include(new string[] { "counter", "_id" });
var m = collection.FindAndModify(query, sortBy, update, fields, false, false);
I wonder what should I write in place of ??? to select all the documents!?
Use an empty QueryDocument:
var query = new QueryDocument();
But keep in mind that FindAndModify will only modify the first matching document.
I need to select User Name from the collection of Users. I do it in a such way:
MongoCollection<Enums> coll = Db.GetCollection<Enums>("Users");
var query = Query.EQ("_id", id);
var res = coll.FindOne(query);
var name = res.Name;
var url = res.UserUrl; //or some more fields, not just Name
Assuming that User document can contain a lot of data, and there is no need to transfer the whole user document, how to select only a few distinct fields, using official C# driver?
You'll have to use a function that returns a MongoCursor.
In the MongoCursor you can specify the fields you want to return.
var result = Db.GetCollection<Enums>("Users").FindAll();
result.Fields = Fields.Include(new [] {"Name"});;
foreach (var user in result)
{
Console.WriteLine(user.Name);
}