From Clause
Just as a rule declaration specifies the scope of the rule, the from
clause specifies the scope of the query. The items in the from
clause must exist in the project ontology.
Using Strings (Instead of Variables) in From Clauses
Bind variables cannot be used in the from
clause—you cannot use select * from $someConcept.
However, to achieve a similar result you can use a new string to construct the query as shown in the following examples:
String conceptName1 = "/Concepts/Concept1"; Query.create("newQuery1", "select * from " + conceptName1); String conceptName2 = "/Concepts/Concept2"; Query.create("newQuery2", "select * from " + conceptName2);
Continuous Queries
The from
clause in a continuous query can specify window policies. See Overview of Continuous Queries for more information.
Examples
The select
and from
clauses are required for all queries.
select * from /Concepts/Address as A select * from /Concepts/Customer B select * from /EntityA as A select * from /EntityB B select * from /EntityX, /EntityY, /EntityZ