使用 C# 和流畅的库动态构建 Mongo 查询
dynamically building a Mongo Query using C# and the fluent library
我正在尝试构建一个 mongo 查询,我几乎可以在 Linq 中使用它(95%),但不幸的是,Linq 提供程序似乎缺少执行以下操作的能力相当于 Intersect(coll).Any() 或 Mongo 说法 AnyIn()
我知道,如果我将流畅的库与一些构建器一起使用,我可以构建一个过滤器,它将给我一个 AnyIn() - 但我缺少的是我如何构建整个查询,即初始过滤器,最后的聚合,投影和过滤器?
这是我的 Linq 查询的一个非常接近的近似值 - 只要我不尝试比较过滤器中的集合成员资格,它就可以完全按照要求工作
public List<MyResult> ListMyResults(Expression<Func<MyResult, bool>> filter, int skip, int take)
{
// Limit to tennants on main Entity being queried
var ents = ApplyDataRestrictions(db.GetCollection<Entity>("entities").AsQueryAble());
var children = db.GetCollection<Child>("children").AsQueryable();
var chickens = db.GetCollection<Chicken>("chickens").AsQueryable();
// Join a couple collections for their counts
var result = from ent in ents
join c in children on ent.Id equals c.EntityId into kids
join ck in chickens on ent.Id equals ck.EntityId into birds
// Project the results into a MyResult
select new MyResult
{
Id = ent.Id,
AProperty = ent.AProperty,
SomeCollection = ent.SomeCollection,
SomeOtherCollectionTagsMaybe = ent.SomeOtherCollectionTagsMaybe,
TotalKids = kids.Count(),
TotalChickens = birds.Count()
};
if(filter != null)
{
// Apply the filter that was built up from criteria on the MyResults data shape
result = result.Where(filter);
}
result = result.Skip(skip).Take(take);
return result.ToList()
}
public IQueryable<Entity> ApplyDataRestrictions(IQueryable<Entity> query)
{
... restrict results to only those with my tennant id ...
}
实际上,没有查询生成器和 AnyIn
也可以实现相同的行为。有了 IQueryable
接口,你可以尝试 .Any()
和 Contains()
作为内部谓词
var inMemoryList = new List<int>() { 3, 4, 5 };
var q = from doc in Col.AsQueryable()
where doc.Collection.Any(x => inMemoryList.Contains(x))
select doc;
或
var q2 = Col.AsQueryable().Where(x => x.Collection.Any(y => inMemoryList.Contains(y)));
我正在尝试构建一个 mongo 查询,我几乎可以在 Linq 中使用它(95%),但不幸的是,Linq 提供程序似乎缺少执行以下操作的能力相当于 Intersect(coll).Any() 或 Mongo 说法 AnyIn()
我知道,如果我将流畅的库与一些构建器一起使用,我可以构建一个过滤器,它将给我一个 AnyIn() - 但我缺少的是我如何构建整个查询,即初始过滤器,最后的聚合,投影和过滤器?
这是我的 Linq 查询的一个非常接近的近似值 - 只要我不尝试比较过滤器中的集合成员资格,它就可以完全按照要求工作
public List<MyResult> ListMyResults(Expression<Func<MyResult, bool>> filter, int skip, int take)
{
// Limit to tennants on main Entity being queried
var ents = ApplyDataRestrictions(db.GetCollection<Entity>("entities").AsQueryAble());
var children = db.GetCollection<Child>("children").AsQueryable();
var chickens = db.GetCollection<Chicken>("chickens").AsQueryable();
// Join a couple collections for their counts
var result = from ent in ents
join c in children on ent.Id equals c.EntityId into kids
join ck in chickens on ent.Id equals ck.EntityId into birds
// Project the results into a MyResult
select new MyResult
{
Id = ent.Id,
AProperty = ent.AProperty,
SomeCollection = ent.SomeCollection,
SomeOtherCollectionTagsMaybe = ent.SomeOtherCollectionTagsMaybe,
TotalKids = kids.Count(),
TotalChickens = birds.Count()
};
if(filter != null)
{
// Apply the filter that was built up from criteria on the MyResults data shape
result = result.Where(filter);
}
result = result.Skip(skip).Take(take);
return result.ToList()
}
public IQueryable<Entity> ApplyDataRestrictions(IQueryable<Entity> query)
{
... restrict results to only those with my tennant id ...
}
实际上,没有查询生成器和 AnyIn
也可以实现相同的行为。有了 IQueryable
接口,你可以尝试 .Any()
和 Contains()
作为内部谓词
var inMemoryList = new List<int>() { 3, 4, 5 };
var q = from doc in Col.AsQueryable()
where doc.Collection.Any(x => inMemoryList.Contains(x))
select doc;
或
var q2 = Col.AsQueryable().Where(x => x.Collection.Any(y => inMemoryList.Contains(y)));