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Class DSRG.MW.QueryEngine
java.lang.Object
|
+----DSRG.MW.QueryEngine
- public class QueryEngine
- extends Object
-
DEBUG
- the debug flag
-
main
- a handle to the Main class
-
QueryEngine(Main)
- the constructor takes the handle to the main class as
argument.
-
breakdown_query(View)
- This method creates the queries that are sent to each IS.
-
computeExtent(View)
- This method computes the extent of a view by using the
queryBreakdown() method.
-
reassemble_query(String)
- This method creates the reassembly query for the intermediate
DB from which this view is computed.
main
private Main main
- a handle to the Main class
DEBUG
private static final boolean DEBUG
- the debug flag
QueryEngine
public QueryEngine(Main myMain)
- the constructor takes the handle to the main class as
argument. This is the only connection to the outside world that
the query engine has
computeExtent
public Table computeExtent(View v)
- This method computes the extent of a view by using the
queryBreakdown() method.
- Returns:
- Table for given View .
breakdown_query
private Vector breakdown_query(View v)
- This method creates the queries that are sent to each IS.
koeller 032999, we're replacing iterateClause with VKB-methods
(View_Definition-Object).
- Returns:
- A Vector of ISQuery()'s.
reassemble_query
public String reassemble_query(String viewName)
- This method creates the reassembly query for the intermediate
DB from which this view is computed.
Changed to use MKB
objects instead of iterateClause, koeller 300399
we have a
bug: the reassembly-query has where-clauses without the
relation names. so if we have a join between attributes with
the same name in relations with the same name, the query won't
work
- Returns:
- A String with a SQL statement (standard SQL with SELECT/FROM/WHERE..)
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