Entity Framework Optimization Techniques in EF Loading Only Required Data
Example
One problem often seen in code is loading all the data. This will greatly increase the load on the server.
Let's say I have a model called "location" that has 10 fields in it, but not all the fields are required at the same time. Let's say I only want the 'LocationName' parameter of that model.
Bad Example
var location = dbContext.Location.AsNoTracking()
.Where(l => l.Location.ID == location_ID)
.SingleOrDefault();
return location.Name;
Good Example
var location = dbContext.Location
.Where(l => l.Location.ID == location_ID)
.Select(l => l.LocationName);
.SingleOrDefault();
return location;
The code in the "good example" will only fetch 'LocationName' and nothing else.
Note that since no entity is materialized in this example, AsNoTracking() isn't necessary. There's nothing to be tracked anyway.
Fetching more fields with Anonymous Types
var location = dbContext.Location
.Where(l => l.Location.ID == location_ID)
.Select(l => new { Name = l.LocationName, Area = l.LocationArea })
.SingleOrDefault();
return location.Name + " has an area of " + location.Area;
Same as the example before, only the fields 'LocationName' and 'LocationArea' will be retrieved from the database, the Anonymous Type can hold as many values you want.
