Package com.sap.cds.util.transformations

Class TransformationToSelect

java.lang.Object

com.sap.cds.util.transformations.TransformationToSelect

public class TransformationToSelect
extends Object

Converts CqnTransformations to corresponding clauses of a CqnSelect statement. In SQL, the clauses of SELECT follow this "natural" order:

1. FROM, JOIN
2. WHERE
3. GROUP BY
4. aggregate functions
5. HAVING
6. window functions
7. SELECT
8. DISTINCT
9. UNION/INTERSECT/EXCEPT
10. ORDER BY
11. SKIP/OFFSET
12. TOP/LIMIT/FETCH

If the transformations follow this order, they are simply substituted by the corresponding clauses in `CqnSelect`. If a transformation breaks this order the statement is wrapped into a subquery and the transformation is applied to the subquery. Finally, the clauses of the original CqnSelect are converted to transformations and applied.

Constructor Summary

Constructors

Constructor	Description
TransformationToSelect(Select<?> select)

Method Summary

Modifier and Type	Method	Description
void	applyOrderAndLimit()
void	applyTransformations()
Select<?>	get()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

TransformationToSelect

public TransformationToSelect(Select<?> select)

Method Details

get

public Select<?> get()

applyTransformations

public void applyTransformations()

applyOrderAndLimit

public void applyOrderAndLimit()