Parent interface for all criteria item definitions.
There are 3 types of criteria items:
1. SubSelect criteria item:
Contains a left operand, operator, and a right operand that is a
named criteria. Items of this type should implements the SimpleItem interface.
This type of item can be used for
subselect queries on child/children tables and enforces restriction on a
parent resultset based on criteria on the child/children tables.
2. Nested Row criteria item:
Contains nested criteria rows on the same accessor. Items fo this type
should implements the NestedRowItem iterface. This type of item can
by use to allow nesting or bracketing of where-clause fragments.
3. Attribute Item:
Contains a left operand, operator, and a right operand that can be
attribute values or expressions. Items of this type should implements the
SimpleItem interface. Examples of right operand expression include
proper SQL fragments or expressions with wild characters * or %.
Sets the conjunction of this row. The conjunction will be applied to
connect this row with the previous item in the criteria row.
If an item is created but its conjunction is not set, the default
row-level conjunction for the datacontrol is assumed.