Entity Framework 6.x Code Frist For Oracle 实践与注意点

开发环境

Visual Studio.net 2015/2017

Oracle 11g/12c 数据库

Oracle Client 可以不安装

Asp.net mvc Project

Nuget 组件

EntityFramework 6.1.3
Oracle.ManagedDataAccess 12.1.2400
Oracle.ManagedDataAccess.EntityFramework 12.1.2400

Entity Framework web.config配置

通过nuget安装以上3个组件后，visual studio.net会自动修改web.config的配置信息，会添加以下内容

</configSections>

</providers>

</entityFramework>

<system.data>

</DbProviderFactories>

</system.data>

<oracle.manageddataaccess.client>

</dataSources>

</version>

</oracle.manageddataaccess.client>

</connectionStrings>

有了oracle.manageddataaccess.client就不需要安装Oracle客户端了，descriptpor修改成需要连接的Oracle数据库实例就可以了

创建Model/DbContext

public class Blog

{

public int BlogId { get; set; }

[MaxLength(50)]

public string Url { get; set; }

}

public class MyDbContext: DbContext

{

public MyDbContext() : base("Name=OracleDbContext")

{

Database.SetInitializer<MyDbContext>(null);

}

public DbSet<Blog> Blogs { get; set; }

public DbSet<Post> Posts { get; set; }

protected override void OnModelCreating(DbModelBuilder modelBuilder)

{

//注意：Oracle必须定义成用户名/所有者或是称Schema，（SQL默认是dbo）

modelBuilder.HasDefaultSchema("C##EF1");

//注意：Oracle必须把所有mapping的字段名转换成大写，否则无法在pl/sql developer中用sql查询

modelBuilder.Properties().Configure(x => x.HasColumnName(x.ClrPropertyInfo.Name.ToUpper()));

//注意：Oracle必须把所有mapping的数据库表名转换成大写，否则无法在pl/sql developer中用sql查询

modelBuilder.Types().Configure(c => c.ToTable(c.ClrType.Name.ToUpper()));

长度/NVARCHAR2类型，否则系统会自动创建成NCLOG类型

modelBuilder.Properties<string>().Configure(c => c.HasMaxLength(250));

modelBuilder.Properties<string>().Configure(c => c.HasColumnType("NVARCHAR2"));

}

protected override void OnModelCreating(DbModelBuilder modelBuilder) 可以设定非常多自定义属性，比如ID/主键/一对多/级联删除/命名规则等，具体可以参考以下内容

Entity Framework Fluent API - Configuring and Mapping Properties and Types

Entity Framework Custom Code First Conventions (EF6 onwards)

创建表/同步更新表结构

执行Code first 命令

Run the Enable-Migrations command in Package Manager Console
Add-Migration will scaffold the next migration based on changes you have made to your model since the last migration was created
Update-Database -script will apply any pending migrations to the database

注意：Update-Database -script 系统会生成数据库的DDL脚本，这样可以方便做一些调整后再执行更新到数据库

如果需要多个库（开发库/测试库/生产库）同步更新就可以通过修改脚本来实现

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Entity Framework 6.x Code Frist For Oracle 实践与注意点