Apply Process Rules
The rules defined for the Apply process
dictate what is applied or what is not applied to the
destination databases. Rules can be placed in a positive rule
set or negative rule set. If a rule evaluates to TRUE for a
change and the rule is in the positive rule set for an Apply
process, the Apply process applies the change. If a rule
evaluates to TRUE for a change but the rule is in the negative
rule set for an Apply process, the Apply process discards the
change. If an Apply process has both a positive and a negative
rule set, the negative rule set is always evaluated first and
acts as the first level filter.
Apply process rules for LCR events can be
specified at the following three levels:
A Table rule applies or discards either row
changes resulting from DML changes or DDL changes to a
particular table. The subset rules which configure the table
rules that impact the subset of the rows of a particular
table can also be specified.
A Schema rule applies or discards either
row changes resulting from DML changes or DDL changes to the
database objects in a specified schema.
A Global rule applies or discards either
all row changes resulting from DML changes or all DDL changes in
the queue associated with an Apply process.
Understanding and setting up the right rule
condition is very important for proper data replication flow.
Otherwise, data can be ignored or not applied at all.
The following section presents information
on the apply mechanism and architecture.