{"id":1050,"date":"2017-03-26T17:17:08","date_gmt":"2017-03-26T21:17:08","guid":{"rendered":"http:\/\/www.ObiOberoi.com\/?p=1050"},"modified":"2017-03-26T17:17:08","modified_gmt":"2017-03-26T21:17:08","slug":"can-use-projections-ef-core-absolutely","status":"publish","type":"post","link":"https:\/\/obioberoi.com\/?p=1050","title":{"rendered":"Can I use Projections in EF Core…Absolutely!!"},"content":{"rendered":"

Before we drill into Projections, let’s find out what Projections really are:<\/p>\n

Projection(s) is a powerful feature of LINQ that enables you to perform query operations on a data source, collection etc. It shapes the results of the data being queried into a different structure\/format that the original data source is in.<\/p>\n

It is a process to express queries in order to return a desired set of data other than the entire entity. Projection queries improve the efficiency of your application by only retrieving specific fields from your database.<\/p>\n

A projection query lets you select only the data that is required from your model. It is done, by loading the data into a custom or anonymous type. This significantly improves the performance of your application, especially when you filter out the fields that contain huge amounts of data.<\/p>\n

When you use the Select <\/em>method, you can retrieve scalar properties and also navigation properties to retrieve data in the same query. Please see the code snippet below:<\/p>\n

   private static void Projections()\n        {\n            using (var db = new demo_departmentContext())\n            {\n                var dept = db.Departments.Select(d => new { d.DepId, d.DepName, d.Location })\n                    .Where(d => d.DepName.Contains(\"IT\"))\n                    .ToList();\n                foreach (var item in dept)\n                {\n                    Console.WriteLine(\"{0} - {1} - {2}\", item.DepId, item.DepName, item.Location);\n                }\n                Console.ReadLine();\n            }\n        }\n<\/pre>\n
And following is the output:<\/p>\n
\"EFCoreProjectionsOutput\"As\u00a0 you saw above using projections\u00a0allow us to retrieve a subset of the properties from an object as opposed to the entire object. This causes a smaller amount of data to be returned in the query.<\/span> <\/p>\n","protected":false},"excerpt":{"rendered":"
Before we drill into Projections, let’s find out what Projections really are: Projection(s) is a powerful feature of LINQ that enables you to perform query operations on a data source, collection etc. It shapes the results of the data being … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-1050","post","type-post","status-publish","format-standard","hentry","category-orm"],"_links":{"self":[{"href":"https:\/\/obioberoi.com\/index.php?rest_route=\/wp\/v2\/posts\/1050","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/obioberoi.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/obioberoi.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/obioberoi.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/obioberoi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1050"}],"version-history":[{"count":0,"href":"https:\/\/obioberoi.com\/index.php?rest_route=\/wp\/v2\/posts\/1050\/revisions"}],"wp:attachment":[{"href":"https:\/\/obioberoi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1050"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/obioberoi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1050"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/obioberoi.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1050"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}