You can access Oracle databases in .NET applications using Oracle Data Provider for .NET (ODP.NET) and Microsoft OracleClient for .NET

• Oracle Data Provider for .NET (ODP.NET)

ODP.NET is an optimized ADO.NET provider developed by Oracle, its component name is Oracle.DataAccess (Add Reference list) and namespace is Oracle.DataAccess.Client

Example:

 using Oracle.DataAccess.Client;     -- C#

 Imports Oracle.DataAccess.Client    ' VB.NET

• Microsoft OracleClient for .NET

Microsoft OracleClient is the .NET Framework Data Provider for Oracle developed by Microsoft, its namespace is System.Data.OracleClient

Example:

 using System.Data.OracleClient;     -- C#

 Imports System.Data.OracleClient    ' VB.NET

Note. Microsoft OracleClient is deprecated in .NET 4.0 and will be removed in future .NET versions.