How can I connect to an Oracle Database from C# on Windows 7 x64 in my development environment

Question

I'm having difficulty connecting to an Oracle database on Windows 7x64

My environment is as follows:

• Windows 7x64
• Visual Studio 2012
• Oracle 10g (with a 32 bit client)
• WinForms

I've made the target CPU of all projects explicitly an x86 CPU (as opposed to Any or x86)

I'm connecting using DbProviderFactory.GetFactory

My ConnectionString entry in my app.config looks like this:

<add name="MYORACLE"
connectionString = "User ID=MYPASSWORD;Password=MYPASSWORd;Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=MYHOST)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=MYSERVICE)));"
providerName="System.Data.OracleClient" />

(I've tried it with various styles connection strings with no success)

When I compile the application, it is able to connect fine if I run the executable from the Debug folder. However, if I try to run it within Visual Studio it fails when I open the connection

ORA-06413: Connection not open.\n

Here's an example of how it's being called:

[TestMethod]
public void ConnectToOracle_Success()
{
    var connectionStringSettings = ConnectionBuilder.GetConnectionStringSetting(OracleConnectionName);
    var providerFactory = ConnectionBuilder.GetProviderFactory(connectionStringSettings);
    ConnectionBuilder.ValidateConnectionString(connectionStringSettings);
    using (var connection = providerFactory.CreateConnection())
    {
        Assert.IsNotNull(connection);
        connection.ConnectionString = connectionStringSettings.ConnectionString;
        try
        {
             connection.Open();
        }
        catch (Exception e)
        {
            Assert.Equals(e.Message, "");
        }
    }
}

I've seen something similar with Visual Basic 6 on Windows 7x64, and Oracle not liking the paths where it's installed (i.e., the parenthesis "Programs (x86)"). Is this the same sort of thing, or is there another way to convince Oracle to behave.

Answer 1

This could be a OCI client version issue. See https://community.oracle.com/message/11103466.

I have seen a lot of issues with this. Most of the time this has to do with a ODP.NET assembly (such as Oracle.DataAccess) which is in a different version then the operating system architecture (we are talking bits here).

There are a few things you could do about this:

1. Install both 32- and 64-bit ODP.NET client tools (including OCI for that architecture), free to download from oracle.com.

2. Build your application for a specific processor architecture, such as 32-bit.

3. Use a third party Oracle client connector that is not dependent on OCI (this is what gives the problems). I wouldn't recommend this, since this is most of the time the expensive solution.