Entity Framework With Oracle

虽然EF6都快要出来了,但是对于Oracle数据库,仍然只能用DB first和Model First来编程,不能用Code First真是一个很大的遗憾啊。

好了,废话少说,我们来看看EF中是如何用DB first和Model First来对Oracle编程的。

首先我们要下载ODP.NET这个数据驱动程序,下载链接:http://www.oracle.com/technetwork/topics/dotnet/index-085163.html

安装成功后,我们在VS连接Oracle数据库时就可以选择ODP.NET了,如图:

Model First

模型优先是先建立数据模型,然后再根据模型生成相应的数据库脚本,然后再根据脚本生成数据库。

在项目中新增一个ADO.NET实体模型:OracleModel.edmx,选择“空模型”,再新新建两个实体:Destination与Lodging,如图:

为了看清这两个模型中属性的数据类型,我把他们生成的类也贴出来一下:

View Code
 public partial class Destination
    {
        public Destination()
        {
            this.Lodging = new HashSet<Lodging>();
        }
    
        public int DestinationId { get; set; }
        public string Name { get; set; }
        public string Country { get; set; }
        public byte Photo { get; set; }
        public string Description { get; set; }
    
        public virtual ICollection<Lodging> Lodging { get; set; }
    }

 public partial class Lodging
    {
        public int LodgingId { get; set; }
        public string Name { get; set; }
        public string Owner { get; set; }
        public bool IsResort { get; set; }
        public decimal MilesFromNearestAirport { get; set; }
        public int DestinationDestinationId { get; set; }
    
        public virtual Destination Destination { get; set; }
    }

实体模型的空白处,右键-属性,在打开的OracleModel模型属性窗口,设置一些属性,将DDL生成模板改成:SSDLToOracle.tt (VS),数据库架构名称改成:GYOUNG(这是我自己测试的Oracle数据库的用户名,大家可根据自己的更改),数据库生成工作流改成:Generate Oracle Via T4 (TPT).xaml (VS)

为了让EF更好的明白.NET中的数据类型与Oracle中数据类型间的对应关系。我们可以将下面的配置文件加到app.config中。

  <oracle.dataaccess.client>
    <settings>
      <add name="bool" value="edmmapping number(1,0)" />
      <add name="byte" value="edmmapping number(3,0)" />
      <add name="int16" value="edmmapping number(4,0)" />
      <add name="int32" value="edmmapping number(9,0)" />
      <add name="int64" value="edmmapping number(18,0)" />
    </settings>
  </oracle.dataaccess.client>

现在我们就可以生成数据库的相应脚本了。

在空白处右键,选择“根据模型生成数据库”

然后建立好数据连接,如图:

点击下一步,然后就会生成相应的数据脚本。

View Code
-- Creating table 'Destinations'
CREATE TABLE "GYOUNG"."Destinations" (
   "DestinationId" NUMBER(9,0) NOT NULL,
   "Name" NCLOB NOT NULL,
   "Country" NCLOB NOT NULL,
   "Photo" NUMBER(3,0) NOT NULL,
   "Description" NCLOB NOT NULL
);

-- Creating table 'Lodgings'
CREATE TABLE "GYOUNG"."Lodgings" (
   "LodgingId" NUMBER(9,0) NOT NULL,
   "Name" NCLOB NOT NULL,
   "Owner" NCLOB NOT NULL,
   "IsResort" NUMBER(1,0) NOT NULL,
   "MilesFromNearestAirport" NUMBER(38,0) NOT NULL,
   "DestinationDestinationId" NUMBER(9,0) NOT NULL
);


-- --------------------------------------------------
-- Creating all PRIMARY KEY constraints
-- --------------------------------------------------

-- Creating primary key on "DestinationId"in table 'Destinations'
ALTER TABLE "GYOUNG"."Destinations"
ADD CONSTRAINT "PK_Destinations"
   PRIMARY KEY ("DestinationId" )
   ENABLE
   VALIDATE;


-- Creating primary key on "LodgingId"in table 'Lodgings'
ALTER TABLE "GYOUNG"."Lodgings"
ADD CONSTRAINT "PK_Lodgings"
   PRIMARY KEY ("LodgingId" )
   ENABLE
   VALIDATE;


-- --------------------------------------------------
-- Creating all FOREIGN KEY constraints
-- --------------------------------------------------

-- Creating foreign key on "DestinationDestinationId" in table 'Lodgings'
ALTER TABLE "GYOUNG"."Lodgings"
ADD CONSTRAINT "FK_DestinationLodging"
   FOREIGN KEY ("DestinationDestinationId")
   REFERENCES "GYOUNG"."Destinations"
       ("DestinationId")
   ENABLE
   VALIDATE;

-- Creating index for FOREIGN KEY 'FK_DestinationLodging'
CREATE INDEX "IX_FK_DestinationLodging"
ON "GYOUNG"."Lodgings"
   ("DestinationDestinationId");

-- --------------------------------------------------
-- Script has ended
-- --------------------------------------------------

我们只要将脚本到数据库中执行一下就可以生成相应的表了。分析一下生成的SQL语句,有主键,外键,但并没有为主键设置自增长。Oracle设置自增长也是一个很蛋疼的问题,要通过设置相应的Sequences和Triggers来实现,习惯了SQL SERVER的IDENTITY,对于这个还真不爽。这里我们不管它,就自己插入主键好了。下面是测试代码:

View Code
 using (OracleModelContainer context = new OracleModelContainer())
            {
                var destination = new Destination
                {
                    DestinationId=1,
                    Country = "Indonesia",
                    Description = "EcoTourism at its best in exquisite Bali",
                    Name = "Bali"
                };
                var lodging = new Lodging
                {
                    LodgingId=1,
                    Owner="Jshon",
                    Name = "Top Notch Resort and Spa",
                    MilesFromNearestAirport = 30,
                    IsResort=true,
                    Destination=destination
                };
                context.Lodgings.Add(lodging);
                context.SaveChanges();
            }

通过VS连接Oracle可以看到数据插入成功。

DB First

DB First顾名思义就是在先建好数据库,再进行编程。我们新建一个项目,就以刚刚生成的那再张表来编程。

在新建项目中添加一个“ADO.NET 实体数据模型”:DBModel.edmx,选择“从数据库生成”

设置好连接串

选择表

点击完成,就会生成相应的模型。

我们来检索一下刚刚插入的数据。

View Code
 using (Entities context = new Entities())
            {
                var des = context.Destinations.FirstOrDefault();
                var log = context.Lodgings.FirstOrDefault();
                Console.WriteLine("Lodging  Name:" + log.Name + " Owner:" + log.Owner);
                Console.WriteLine("Destination   Name:" + des.Name + " Country:" + des.Country);
            }

结果如图。

PS:在DB First模式中,更要将Model First中所说的映射配置文件加入App.config中,不然很多数据类型映射会出错。

 

伪Code First

见我的另一篇博客:Entity Framework Code First在Oracle下的伪实现

 

posted @ 2013-02-04 23:28 Gyoung 阅读(...) 评论(...) 编辑 收藏