Sample for Entity Framework 6 + Code First + Oracle 12c - entity-framework

Question

I have a problem with a Visual Studio solution using Entity Framework 6 + Code First + Oracle 12c. I'm not sure it is properly configured, or if I missed something simple.
I tried to look for a sample project as a start, but was not able to find - google search, stackoverflow etc.
Is there a minimalistic sample project somewhere, which tries to create the database when runs?
Update: Just to make sure, I'm not asking anyone to create a sample for me. Before I'll do it, I want to make sure there is really no existing sample (which is strange for me, but very well might be the case).

Answer 1

I managed to create a working sample. Found some (not so) documented strange behaviors resulting in run time errors along the way.
Here is the full sample source: https://drive.google.com/file/d/0By3P-kPOnpiGRnc0OG5ZTDl6eGs/view?usp=sharing&resourcekey=0-ecT1EU81wJOQWokVDr_r9w
I created the sample with Visual Studio 2013. Used nuget to pull
EntityFramework 6.1.3
Official Oracle ODP.NET, Managed Entity Framework Driver 12.1.021
The important parts are
Program.cs
Context.cs
TestEntity.cs
App.config
I omit
packages.config
AssemblyInfo.cs
csproj, sln files
I also omit namespaces.
using System.Data.Entity;
public class Program
{
private static void Main(string[] args)
{
string connStr =
"Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=***server***)(PORT=1521))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=***SERVICE***)));Persist Security Info=True;User ID=***User***;Password=***password***";
Database.SetInitializer(new DropCreateDatabaseIfModelChanges<Context>());
//Database.SetInitializer(new DropCreateDatabaseAlways<Context>());
Context context = new Context(connStr);
TestEntity te = new TestEntity();
te.Id = 1;
te.Name = "Test1";
context.TestEntities.Add(te);
context.SaveChanges();
}
}
using System.Data.Entity;
public class Context : DbContext
{
public Context(string nameOrConnectionString)
: base(nameOrConnectionString)
{
}
public virtual DbSet<TestEntity> TestEntities { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.HasDefaultSchema("OTS_TEST_EF");
modelBuilder.Entity<TestEntity>()
.Property(e => e.Id)
.HasPrecision(9, 2);
base.OnModelCreating(modelBuilder);
}
}
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
[Table("TestEntity")]
public class TestEntity
{
[Column(TypeName = "number")]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public decimal Id { get; set; }
[StringLength(100)]
public string Name { get; set; }
}
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework"
type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
requirePermission="false"/>
<section name="oracle.manageddataaccess.client"
type="OracleInternal.Common.ODPMSectionHandler, Oracle.ManagedDataAccess, Version=4.121.2.0, Culture=neutral, PublicKeyToken=89b483f429c47342"/>
</configSections>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/>
</startup>
<entityFramework>
<!--<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework"/>-->
<providers>
<!--<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer"/>-->
<provider invariantName="Oracle.ManagedDataAccess.Client"
type="Oracle.ManagedDataAccess.EntityFramework.EFOracleProviderServices, Oracle.ManagedDataAccess.EntityFramework, Version=6.121.2.0, Culture=neutral, PublicKeyToken=89b483f429c47342"/>
</providers>
</entityFramework>
<system.data>
<DbProviderFactories>
<remove invariant="Oracle.ManagedDataAccess.Client"/>
<add name="ODP.NET, Managed Driver" invariant="Oracle.ManagedDataAccess.Client" description="Oracle Data Provider for .NET, Managed Driver"
type="Oracle.ManagedDataAccess.Client.OracleClientFactory, Oracle.ManagedDataAccess, Version=4.121.2.0, Culture=neutral, PublicKeyToken=89b483f429c47342"/>
</DbProviderFactories>
</system.data>
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<publisherPolicy apply="no"/>
<assemblyIdentity name="Oracle.ManagedDataAccess" publicKeyToken="89b483f429c47342" culture="neutral"/>
<bindingRedirect oldVersion="4.121.0.0 - 4.65535.65535.65535" newVersion="4.121.2.0"/>
</dependentAssembly>
</assemblyBinding>
</runtime>
<!--<oracle.manageddataaccess.client>
<version number="*">
<dataSources>
<dataSource alias="SampleDataSource" descriptor="(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=INFOTEST))) "/>
</dataSources>
</version>
</oracle.manageddataaccess.client>-->
<!--<connectionStrings>
<add name="OracleDbContext" providerName="Oracle.ManagedDataAccess.Client"
connectionString="Data Source=(DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))(CONNECT_DATA =(SERVER = DEDICATED)(SERVICE_NAME = INFOTEST)));Persist Security Info=True;User ID=user;Password=password"/>
</connectionStrings>-->
</configuration>
The strange thing I found on the way:
Adding any of the following TypeNames will result in "Sequence contains no matching element" error.
/*[Column(TypeName = "numeric")]*/
/*[Column(TypeName = "number(18,0)")]*/
/*[Column(TypeName = "number(18,2)")]*/
Indicating precision with scale 0
modelBuilder.Entity<TestEntity>().Property(e => e.Id).HasPrecision(9, 0);
Will result in
Schema specified is not valid. Errors:
(7,12) : error 2019: Member Mapping specified is not valid. The type 'Edm.Decimal[Nullable=False,DefaultValue=,Precision=9,Scale=0]' of member 'Id' in type 'EF6_Oracle12c_CF.TestEntity' is not compatible with 'OracleEFProvider.number
Omitting the
modelBuilder.HasDefaultSchema("OTS_TEST_EF");
line will result in
ORA-01918: user does not exists
It is also happened that I got
ORA-00955: name is already being used by existing object
or
Model compatibility cannot be checked because the database does not contain model metadata. Model compatibility can only be checked for databases created using Code First or Code First Migrations.
I managed to overcome those by enabling the
Database.SetInitializer(new DropCreateDatabaseAlways<Context>());
line, instead of the DropCreateDatabaseIfModelChanges mode.

Answer 2

This has the a good sample if you are still interested . It is available on 11 g .
http://www.oracle.com/webfolder/technetwork/tutorials/obe/db/dotnet/CodeFirst/index.html

Answer 3

Here's a link to a sample from Oracle on using EF Code First, Migration and Visual Studio.
Oracle Learning Library on EF Code First and Code First Migration
I'm actually almost finishing up a project that uses VS, 12c and EF and the link was a good starting point. There was no particular issue about 12c that I saw.

Answer 4

I have a test project on github that I used to try out examples of EF6 migrations on Oracle. The code that works for me (to programatically execute all pending migrations) is here. My use case is likely common - I need to be able to deploy my application to various environments and data centres and have it do "the right thing" to work with the environment's copy of my application database.
The important bit is
//Arrange
Configuration config = new Configuration();
DbMigrator migrator = new DbMigrator(config);
Console.WriteLine("Migrating...");
foreach (string s in migrator.GetPendingMigrations())
{
//Act
Console.WriteLine("Applying migration {0}", s);
Action act = () => migrator.Update(s);
//Assert
act.ShouldNotThrow();
}

Answer 5

I spent days fixing this issue... Finally I solved it:
The table did not exist. I checked many times and refreshed, but the problem was not in the table itself, it was with the sequence. Every table in Oracle creates a sequence object to increase the id. So, if you delete the table make sure to drop the sequence as well, otherwise when you migrate again, it will give you ORA-00955: name is already used by an existing object.
So, the real problem is in the sequence, not in the table. But you cannot create new sequence because it already exists. It is not deleted when you delete the table, it should be deleted manually.
I hope this will help someone.