EF 6.复杂查询。 搜索和过滤

Question

I'm using Entity Framework 6 in my asp.net mvc application. I have complex query to database that causes about 15 tables. Query includes searching and filtering. This query execution is slow (about 800 ms on local machine).

query.Include(i => i.Customer) 
     .Include(i => i.Address) 
      ... 
     .Include(i => i.Photos)
     .Select(x => new {
      ...
      x.Address.City,
      CustomerName = i.Customer != null ? i.Customer.Name : "",
      ...
    });

...
//searching & filtering
// searchFilter.PropertyName and searchFilter.PropertyValue - strings!
// for example searchFilter.PropertyName = 'CustomerName'
 query = query.Where(String.Format("{0} == {1}", searchFilter.PropertyName, searchFilter.PropertyValue));
// PageIndex = 20
 query = query.Skip(PageIndex * PageSize).Take(PageSize)
...
 var result = query.ToList();
...

The problems:

1. Eager loading not working properly - MiniProfiler shows duplicate requests of Address table
2. Such searching (using 'Contains') is very limited, because I have to create anonymous type object with properties like Customer for checking if Customer is not null (or more complex actions) and have to hard-code somewhere PropertyName's strings (for instance in javascript file that calls ajax request).

Are there other ways to do it?

Answer 1

some remarks:

• you don't need to include(i => i.Address) to select x.Address.City , nor to test any Address property in a where clause
• as long as you have an IQueryable bind to an Sql Server, CustomerName = i.Customer != null ? i.Customer.Name : "" CustomerName = i.Customer != null ? i.Customer.Name : "" can be replaced by CustomerName = i.Customer.Name ?? "" CustomerName = i.Customer.Name ?? ""

Not sure this can have significant performance impact but...

Otherwise, as often, index creation is a path to performance improvement.