Oracle Database for Windows stores its configuration information in a repository (the registry) that is organized in a tree format.
Although Registry Editor lets you view and modify registry keys and parameter values, you typically are not required to do so. In fact, you can render your system useless if you make incorrect changes. Therefore, only advanced users must edit the registry. Back up your system before making any changes in the registry.
Parameters in the Registry Editor appear as a string, consisting of three components:
Value class or type of entry
For example, parameter
ORACLE_SID can have the following entry in the registry:
String value with a
REG_EXPAND_SZ(for an expandable string), or a
REG_MULTI_SZ(for multiple strings) prefix to identify a parameter value entry as a data string
Binary value with a
REG_QWORDprefix to identify a value entry as a
qword(hexadecimal data) entry
Most Oracle Database for the Windows parameter values are string types. Use Oracle Universal Installer defaults when a type is not given.