LINQ クエリ

LINQ queries demonstrate how to operate and query the CSV objects wrapped in an Entity Framework data model. Below are some examples of LINQ queries supported by the Entity framework.

Contains

Retrieve all records from the Books table that contains "Agriculture" in their Industry name.

C#	コードのコピー
var histories = from p in context.Books where p.Industry_name.Contains("Agriculture") //Agricultureを含むIndustry名を表示するには、Containsを使用します。 select p;

Count

Count all entities that match a given criterion.

C#	コードのコピー
var _count = (from p in db.SampleCSV select p).Count(); //選択されたレコードの数に基づいてクエリをカウントします。

Select and Filter

Select records from the table SampleCSV that belong to Year equal to 2011.

C#	コードのコピー
var histories = from p in db.SampleCSV where p.Year== 2011 select p;

Limit

Select first 2 records.

C#	コードのコピー
var histories = (from p in db.SampleCSV select p).Take(2); //レコードを2 個取得します。

Order By

Sort records form the table SampleCSV by Year in descending order.

C#	コードのコピー
var histories = (from p in db.SampleCSV orderby p.Year descending //Order Byの実装 select p).Take(2); //レコードを2 個取得します。

Group By

Group records from the SampleCsvs table based on the Age property. The groups are then ordered in descending order based on the Age.

C#	コードのコピー
var sampleTable = context.SampleCsvs.AsEnumerable(); var querySample = from b in sampleTable group b by b.Age into newGroup orderby newGroup.Key descending select newGroup;