參考頁面: http://www.yuanjiaocheng.net/Entity/first.html http://www.yuanjiaocheng.net/Entity/jieshao.html http://www.yuanjiaocheng.net/entity/tixijiegou.h ...
參考頁面:
http://www.yuanjiaocheng.net/Entity/first.html
http://www.yuanjiaocheng.net/Entity/jieshao.html
http://www.yuanjiaocheng.net/entity/tixijiegou.html
http://www.yuanjiaocheng.net/entity/setenvrionment.html
http://www.yuanjiaocheng.net/entity/createdatamodel.html
雖然EF6都快要出來了,但是對於Oracle資料庫,仍然只能用DB first和Model First來編程,不能用Code First真是一個很大的遺憾啊。
好了,廢話少說,我們來看看EF中是如何用DB first和Model First來對Oracle編程的。
首先我們要下載ODP.NET這個數據驅動程式,下載鏈接:http://www.oracle.com/technetwork/topics/dotnet/index-085163.html
安裝成功後,我們在VS連接Oracle資料庫時就可以選擇ODP.NET了,如圖:
Model First
模型優先是先建立數據模型,然後再根據模型生成相應的資料庫腳本,然後再根據腳本生成資料庫。
在項目中新增一個ADO.NET實體模型:OracleModel.edmx,選擇“空模型”,再新新建兩個實體:Destination與Lodging,如圖:
為了看清這兩個模型中屬性的數據類型,我把他們生成的類也貼出來一下:
View Codepublic 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; } }
實體模型的空白處,右鍵-屬性,在打開的OracleModel模型屬性視窗,設置一些屬性,將DDL生成模板改成:SSDLToOracle.tt (VS),資料庫架構名稱改成:GYOUNG(這是我自己測試的Oracle資料庫的用戶名,大家可根據自己的更改),資料庫生成工作流改成:Generate Oracle Via T4 (TPT).xaml (VS)
為了讓EF更好的明白.NET中的數據類型與Oracle中數據類型間的對應關係。我們可以將下麵的配置文件加到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>
現在我們就可以生成資料庫的相應腳本了。
在空白處右鍵,選擇“根據模型生成資料庫”
然後建立好數據連接,如圖:
點擊下一步,然後就會生成相應的數據腳本。
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 -- --------------------------------------------------
我們只要將腳本到資料庫中執行一下就可以生成相應的表了。分析一下生成的SQL語句,有主鍵,外鍵,但並沒有為主鍵設置自增長。Oracle設置自增長也是一個很蛋疼的問題,要通過設置相應的Sequences和Triggers來實現,習慣了SQL SERVER的IDENTITY,對於這個還真不爽。這裡我們不管它,就自己插入主鍵好了。下麵是測試代碼:
View Codeusing (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(); }
通過VS連接Oracle可以看到數據插入成功。
DB First
DB First顧名思義就是在先建好資料庫,再進行編程。我們新建一個項目,就以剛剛生成的那再張表來編程。
在新建項目中添加一個“ADO.NET 實體數據模型”:DBModel.edmx,選擇“從資料庫生成”
設置好連接串
選擇表
點擊完成,就會生成相應的模型。
我們來檢索一下剛剛插入的數據。
View Codeusing (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); }
結果如圖。
PS:在DB First模式中,更要將Model First中所說的映射配置文件加入App.config中,不然很多數據類型映射會出錯。
偽Code First
見我的另一篇博客:Entity Framework Code First在Oracle下的偽實現