Linq UserInfo概述
在向大家詳細(xì)介紹Linq UserInfo之前,首先讓大家了解下linq語(yǔ)法,然后全面介紹Linq UserInfo。
前兩天剛剛下載了Orcas beta 1,今天來(lái)玩一下傳說(shuō)中的linq,看看怎么通過(guò)linq語(yǔ)法來(lái)操作數(shù)據(jù)庫(kù)。首先創(chuàng)建一個(gè)Console Application,然后創(chuàng)建一個(gè)名稱為DBForums.mdf的Service-based Database。然后在DBForums.mdf中添加一個(gè)名稱為L(zhǎng)inq UserInfo的表。
添加完成后在工程中添加一個(gè)Linq to SQL項(xiàng),項(xiàng)名稱設(shè)置為DBForums.dbml,然后在Server Explorer中將DBForums.mdf中的Linq UserInfo拖放到DBForums.dbml的設(shè)計(jì)界面上。在程序中就可以訪問(wèn)DBForums數(shù)據(jù)庫(kù)了。
- 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 {.UserName = "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()
因?yàn)樵贒BForums.dbml中定義了Linq UserInfo,因此在代碼中可以訪問(wèn)。首先定義了一個(gè)Linq UserInfo數(shù)組,然后可以通過(guò)Linq查詢,通過(guò)DBForums.dbml的DBForumsDataContext對(duì)象執(zhí)行插入和數(shù)據(jù)庫(kù)查詢操作。
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