VS 2010 C＃Express上的Oracle数据库连接失败

Question

I am new to VS and database. The project I was working on is trying to moderize an old software from VB6 to VS 2010 C#. This requires to search an external database. So I am trying to connect to that database by using OracleConnection(). I am using Visual Studio 2010 Express on Windows 7 Enterprise. I downloaded the Oracle Data Access Components (ODAC 11.2 Release 5 which is the newest, 32bit). The TNSNAMES.ora file and connection string were both correctly settled.

Right now I can use Sql*Plus to connect to the database. Also the old VB6 version software works well in retrieving information from the database(it won't do the work if I did not have ODAC and set up the tnsnames.ora correctly). But, my VS C# does not. It cannot open the connection. The error message is "ORA-12545: Connect failed because target host or object does not exist". And if I changed the DB host address to IP address, it would give me " ORA-12560: TNS:protocol adapter error".

I assume there is a problem with the VS 2010 Express IDE. Does anyone has any idea on that? I tried to reinstall the ODAC and it does not help. Thanks so much in advance.

My code is exactly the same as here connect to oracle XE using c# 2010 express

Update--Solved

I finally figured out this question. In my case, this is somehow related with the DLL in Global Assembly Cache. I found my project is compiling against an odd ODAC designed for .NET 2.0. I tried to redirect the reference of OracleDBAccess but did not help. Then I started a new project, set up the reference right and then copied all the code there. It worked out in the end.

Answer 1

The difference is SqlPlus uses a different data provider to connect than .Net. I have a blog post that talks about the minimum requirements needed for .net and oracle to work together. The main points to consider is to make sure you have the correct data provider (32 / 64 bit) and your oracle bin folder is in the path statement for the OS.

The difference is SqlPlus uses a different data provider to connect than .Net. I have a blog post that talks about the basic requirements.

Blog Post Link

-Text from Post

Download the latest Oracle 11g2 client software from Oracle.

Note – Be sure to determine which bit level you need if using a 64 bit operating system. If your apps are compiled to 32 bit specifically then you must use the 32 bit oracle client. If they are compiled to run natively – then you must use the 64 bit oracle client software.

1. Extract the zip file to a directory

2. Open the folder and launch the setup.exe file as an administrator

3. Select the custom option in Step 1 of 8 for what type of Installation you want and click next

4. Now choose the Oracle Data Provider for .NET option and click next

5. Complete the remaining steps using the default options

6. Once complete – navigate to the following folder

   [installation path]\\product\\11.2.0\\client_1\\network

7. Create a new folder named admin

8. Copy an existing sqlnet.ora and tnsnames.ora file into the admin directory

9. Test the installation with a .net application or you can use one the OracleConnectionTesting utilities provided on this blog here

.Net Testing Utility for Oracle