The following Data Guard configurations using cascaded destinations are supported.
A. Primary Database > Physical Standby Database with cascaded destination > Physical Standby Database
B. Primary Database > Physical Standby Database with cascaded destination > Logical Standby Database
A physical standby database can support a maximum of nine (30 as of Version 11.2) remote destinations.
Physical Standby Forwarding Redo to a Logical Standby :
1. Users can connect to Logical Standby database and they can access
2. Instead of querying primary database they can use logical standby database.
3. without any additional overhead on your primary system, and without consuming any additional transatlantic bandwidth.
The following data types will not support in Logical standby database just check your application before implementing logical standby
b. Collections (including VARRAYS and nested tables)
c. Multimedia data types (including Spatial, Image, and Oracle Text)
d. ROWID, UROWID
e. User-defined types
f. LOBs stored as SecureFiles
g. XMLType stored as Object Relational
h. Binary XML