How to operate the database through linq syntax
Editor to share with you how to operate the database through linq syntax, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!
First create a Console Application, and then create a Service-based Database named DBForums.mdf. Then add a table named Linq UserInfo to the DBForums.mdf.
After adding, add a Linq to SQL item to the project with the item name set to DBForums.dbml, and then drag and drop the Linq UserInfo in DBForums.mdf in Server Explorer onto the design interface of DBForums.dbml. You can access the DBForums database in the program.
Private db As New DBForumsDataContext Dim users () = {_ New UserInfo With {. UserName = "chenrui", _ .password = "12345", _ .Address = "HU", _ .CreateTime = Now}, _ New UserInfo With {. UserName = "Li", _ .Password = "223344", _ .Address = "Bei", _ .CreateTime = Now}, _ New UserInfo With {.password = "Zhang", _ .password = "223344", _ .address = "Bei" _ .CreateTime = Now} _} 'Select Dim UserFromBei = From UserInfo In users Where UserInfo.Address = "Bei" For Each u In UserFromBei Console.WriteLine (u.UserName) Next' Insert For Each u In users db.UserInfos.Add (u) Next db.SubmitChanges () 'select from db Dim q = From c In db.UserInfos Select c.UserName For Each uName In q Console.WriteLine ("Selected:" + uName) Next Console.ReadLine ()
Because Linq UserInfo is defined in DBForums.dbml, it can be accessed in code. You first define a Linq UserInfo array, and then you can perform insert and database query operations through Linq queries and through DBForums.dbml 's DBForumsDataContext objects.
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