__call__ (
        where=None,
        join=(),
        outer=(),
        rename=(),
        keep=(),
        calc=(),
        groupBy=(),
        )

Return a new RV based on select/project/join operations as follows:

where

specify a condition that all rows of the new RV must meet (equivalent to the relational algebra select operation).

join

an iterable of RV's that will be inner-joined with this RV (if no where is supplied, this is a cartesian product.)

outer

an iterable of RV's that will be outer-joined with this RV's inner-joined portions.

keep

a sequence of the names of the columns that should be kept in the new RV. Supplying a non-empty value here is equivalent to the relational algebra project operation.

rename

a sequence of (oldName,newName) tuples specifying columns to be renamed. The old columns are automatically "kept", so if you mix rename and keep, you do not need to list renamed columns in the keep argument.

calc

a sequence of (name,DV) pairs specifying computed columns to include in the new RV. These columns are always added under the given names, so keep and rename have no effect on the new columns.

groupBy

a sequence of the names of the columns that the resulting RV should be summarized on. These columns will be automatically "kept", so if you mix groupBy and keep, you do not need to list group-by columns in the keep argument. Note that when using groupBy, you should only keep or calculate columns that represent aggregates, or else an error will occur.

__cmp__ ( other )

Relation variables must be comparable to each other

__getitem__ ( columnName )

Return the IRelationAttribute for the named column

__hash__ ( other )

Relation variables must be hashable

attributes ()

Return a peak.util.Graph mapping names->relation attributes

clone ()

Return a deepcopy()-like clone of the RV

getCondition ()

Return any select() or join condition applying to this RV

getDB ()

Return an object indicating the responsible DB, or None if mixed

getInnerRVs ()

Return sequence of inner-join RV's, or (self,) if not a join

getOuterRVs ()

Return sequence of outer-join RV's, or () if not outer join

getReferencedRVs ()

Return sequence of all RVs used in this RV (eg: joins,subqueries)

keys ()

Return a sequence of column names