documentdb与linq一起加入 [英] documentdb join with linq
问题描述
我正在尝试使用linq在DocumentDb上运行以下查询
I am trying to run the following query on DocumentDb with linq
SELECT p.id
FROM p JOIN filter IN p.Filters
WHERE filter.Id = "686e4c9c-f1ab-40ce-8472-cc5d63597263"
OR filter.Id = "caa2c2a0-cc5b-42e3-9943-dcda776bdc20"
我的json就是这样
{
"id": "a3dc570b-26e2-40a9-8777-683186965f78",
"Filters": [
{
"Id": "686e4c9c-f1ab-40ce-8472-cc5d63597263"
},
{
"Id": "caa2c2a0-cc5b-42e3-9943-dcda776bdc20"
}
]
}
我发现我应该使用SelectMany进行联接,但是我无法使其正常工作,我尝试了不同的尝试,但始终会遇到运行时错误.
I found that I'm supposed to use SelectMany to do the join, but I can't get it to work, I've tried different things but always get runtime errors.
这是我尝试过的查询,它给出指定的参数超出有效值范围.参数名称:意外的SQL标量表达式种类转换"
edit: Here's the query I've tried, this gives "Specified argument was out of the range of valid values.Parameter name: Unexpected Sql Scalar expression kind Conversion"
public void TryOutQuery(IEnumerable<string> ids)
{
var options = new FeedOptions { MaxItemCount = 10, RequestContinuation = "" };
var queryable = _client.CreateDocumentQuery<PostModel>(UriFactory.CreateCollectionUri(_collectionConn.DatabaseName, _collectionConn.CollectionName), options)
.SelectMany(p => p.Filters
.Where(f => ids.Contains(f.Id))
.Select(f => p)
.Where(post => post.Status == PostStatus.Published)
)
;
var query = queryable.AsDocumentQuery();
var asyn = query.ExecuteNextAsync<PostModel>();
var result = asyn.Result;
}
我还尝试了另一种顺序,该顺序给出了查询输出类型不一致的类型:Post.PostModel和Post.Filter"
I also tried in another order, which gives "Inconsistent types for query output type: Post.PostModel and Post.Filter"
public void TryOutQuery(IEnumerable<string> ids)
{
var options = new FeedOptions { MaxItemCount = 10, RequestContinuation = "" };
var queryable = _client.CreateDocumentQuery<PostModel>(UriFactory.CreateCollectionUri(_collectionConn.DatabaseName, _collectionConn.CollectionName), options)
.Where(p => p.Status == PostStatus.Published)
.SelectMany(p => p.Filters
.Where(f => ids.Contains(f.Id))
.Select(f => p)
)
;
var query = queryable.AsDocumentQuery();
var asyn = query.ExecuteNextAsync<PostModel>();
var result = asyn.Result;
}
这是我的模特
public class Filter
{
public Filter(string id)
{
Id = id;
}
public String Id { get; set; }
}
public class PostModel
{
public PostModel()
{
_filters = new List<Filter>();
}
[JsonProperty("id")]
public String Id { get; set; }
//Since DocumentDb doesn't work properly with IList
public IEnumerable<Filter> Filters { get { return _filters; } }
private IList<Filter> _filters;
public PostStatus Status { get; set; }
public void AddFilter(string filterId)
{
_filters.Add(new Filter(filterId));
}
}
public enum PostStatus
{
Draft,
Published,
Deleted
}
推荐答案
我将使用带有两个JOIN和一个过滤器的查询作为示例:
I'll use a query w/ two JOINs and a filter as an example:
// SQL
var familiesChildrenAndPets = client.CreateDocumentQuery<dynamic>(collectionLink,
"SELECT f.id as family, c.FirstName AS child, p.GivenName AS pet " +
"FROM Families f " +
"JOIN c IN f.Children " +
"JOIN p IN c.Pets " +
"WHERE p.GivenName = 'Fluffy'");
// LINQ
var familiesChildrenAndPets = client.CreateDocumentQuery<Family>(collectionLink)
.SelectMany(family => family.Children
.SelectMany(child => child.Pets
.Where(pet => pet.GivenName == "Fluffy")
.Select(pet => new
{
family = family.Id,
child = child.FirstName,
pet = pet.GivenName
}
)));
查看此DocumentDB Github存储库以获取更多的示例.
Check out this DocumentDB Github repo for more examples.
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