I know Oracle database client provides basic network components and in order to connect to an Oracle database, I have to install it on the client machine. I noticed for Oracle's SQL Developer, I haven't installed any client and it works quite well and can connect to the database without any issues. For Toad, it seems I need to install a client to make it work. My question is, when should I install the Oracle client? How do I know 32bit or 64bit version is needed?
You haven't installed any client because SQL Developer is a Java application, and it uses the Oracle JDBC driver by default, which is located under
jbdc/lib inside the directory of SQL Developer and it is included in the zip file you downloaded. SQL Developer is able to use an Oracle client as well.
Yes, you need to have something for connecting to Oracle databases. It can be a JDBC driver, a .NET provider, or the collection of libraries that is called the "client".
32 or 64 bit depends on the platform and application you use. For modern tools and application you typically go for 64 bit.
You do not have to install an Oracle Client for following cases:
- Your application is based on Java/JDBC, like SQL Developer
- Your application uses the Oracle Data Provider for .NET Managed Driver (ODP.NET Managed Driver)
- Your application uses a third-party Oracle Driver, e.g. Devart or Progress (but I am not 100% sure about that)
For almost any other scenario you have to install an Oracle Client. Whether you have to install 32-bit or 64-bit depends on the architecture of your application. If your application is running in 32-bit then you also have to install the 32-bit Oracle Client, resp. a 64-bit application requires the 64-bit Oracle Client - you cannot mix it!