| A query in the JCR query object model.
The JCR query object model describes the queries that can be evaluated
by a JCR repository independent of any particular query language, such
as SQL.
A query consists of:
- a source. When the query is evaluated, the source evaluates its
selectors and the joins between them to produce a (possibly empty)
set of node-tuples. This is a set of 1-tuples if the query has one
selector (and therefore no joins), a set of 2-tuples if the query has
two selectors (and therefore one join), a set of 3-tuples if the query
has three selectors (two joins), and so forth.
- an optional constraint. When the query is evaluated, the constraint
filters the set of node-tuples.
- a list of zero or more orderings. The orderings specify the order in
which the node-tuples appear in the query results. The relative order
of two node-tuples is determined by evaluating the specified orderings,
in list order, until encountering an ordering for which one node-tuple
precedes the other. If no orderings are specified, or if for none of
the specified orderings does one node-tuple precede the other, then the
relative order of the node-tuples is implementation determined (and may
be arbitrary).
- a list of zero or more columns to include in the tabular view of the
query results. If no columns are specified, the columns available in
the tabular view are implementation determined, but minimally include,
for each selector, a column for each single-valued non-residual property
of the selector's node type.
The query object model representation of a query is created by factory
methods in the
QueryObjectModelFactory .
since:
JCR 2.0 |