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EF架構(gou)~CodeFirst生(sheng)產環境的(de)Migrations

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Migrations即(ji)遷(qian)移，它是EF的code first模式出現的產物，它意思是說(shuo)，將代碼(ma)的變化反映到數據庫(ku)上，這種(zhong)反映有兩(liang)種(zhong)環(huan)(huan)(huan)境(jing)(jing)，一是本地開(kai)(kai)發環(huan)(huan)(huan)境(jing)(jing)，別一種(zhong)是服(fu)務(wu)器的生(sheng)產環(huan)(huan)(huan)境(jing)(jing)，本地開(kai)(kai)發環(huan)(huan)(huan)境(jing)(jing)主要使用包管理工具的update-database即(ji)可完成數據庫(ku)的遷(qian)移（變更），而在生(sheng)產環(huan)(huan)(huan)境(jing)(jing)就顯(xian)得麻煩一些，因為你不會(hui)在生(sheng)產環(huan)(huan)(huan)境(jing)(jing)放(fang)程(cheng)序源代碼(ma)和ＶＳ開(kai)(kai)發工具，哈哈．

本地數據庫遷移請看我的這篇文章

EF架構~CodeFirst數據遷移與防數據庫刪除

服務器上生產環境的數據遷移

如果我們有遷移文件如下

public partial class manager : DbMigration
    {
        /// <summary>
        /// 要在升級過程(cheng)中執行的操作。
        /// &lt;/summary>
        public override void Up()
        {
            DropForeignKey("dbo.WebDataSettings", "WebDataCtrlId", "dbo.WebDataCtrls");
            DropForeignKey("dbo.WebDataSettings", "DepartmentId", "dbo.WebDepartments");
            RenameColumn(table: "dbo.WebDataSettings", name: "DepartmentId", newName: "WebDepartmentsId");
            RenameIndex(table: "dbo.WebDataSettings", name: "IX_DepartmentId", newName: "IX_WebDepartmentsId");
            AddForeignKey("dbo.WebDataSettings", "WebDataCtrlId", "dbo.WebDataCtrls", "ID", cascadeDelete: true);
            AddForeignKey("dbo.WebDataSettings", "WebDepartmentsId", "dbo.WebDepartments", "ID", cascadeDelete: true);
        }

        /// <summary>
        /// 要在(zai)降級過程(cheng)中執(zhi)行(xing)的(de)操作。
 &nbsp;      /// </summary>
        public override void Down()
        {
            DropForeignKey("dbo.WebDataSettings", "WebDepartmentsId", "dbo.WebDepartments");
            DropForeignKey("dbo.WebDataSettings", "WebDataCtrlId", "dbo.WebDataCtrls");
            RenameIndex(table: "dbo.WebDataSettings", name: "IX_WebDepartmentsId", newName: "IX_DepartmentId");
            RenameColumn(table: "dbo.WebDataSettings", name: "WebDepartmentsId", newName: "DepartmentId");
            AddForeignKey("dbo.WebDataSettings", "DepartmentId", "dbo.WebDepartments", "ID");
            AddForeignKey("dbo.WebDataSettings", "WebDataCtrlId", "dbo.WebDataCtrls", "ID");
        }
    }

在本(ben)地ＶＳ中(zhong)執行下(xia)面命令，它將(jiang)生產遷移計劃，即ＳＱＬ語句

Update-Database -Script -SourceMigration: $InitialDatabase -TargetMigration:manage

它將生(sheng)成對應的ＳＱＬ腳本，我們在服(fu)務器(qi)上運行即(ji)可

冪等性

由Migration生(sheng)成的ＳＱＬ腳(jiao)本是(shi)(shi)冪等的，即(ji)，當你多次執(zhi)行ＳＱＬ腳(jiao)本時，產生(sheng)的結果是(shi)(shi)一(yi)樣的，不對有負作用．

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posted @ 2016-07-27 13:31  張占嶺  閱讀(5314)  評論(2)    收藏  舉報