//---------------------------------------------------------------------------
// @function:
// CLogicalAssert::Maxcard
//
// @doc:
// Derive max card
//
//---------------------------------------------------------------------------
CMaxCard
CLogicalAssert::Maxcard
(
IMemoryPool *, // pmp
CExpressionHandle &exprhdl
)
const
{
// in case of a false condition or a contradiction, maxcard should be 1
CExpression *pexprScalar = exprhdl.PexprScalarChild(1);
GPOS_ASSERT(NULL != pexprScalar);
if (CUtils::FScalarConstFalse(pexprScalar) ||
CDrvdPropRelational::Pdprel(exprhdl.Pdp())->Ppc()->FContradiction())
{
return CMaxCard(1 /*ull*/);
}
// if Assert operator was generated from MaxOneRow operator,
// then a max cardinality of 1 is expected
if (NULL != exprhdl.Pgexpr() &&
CXform::ExfMaxOneRow2Assert == exprhdl.Pgexpr()->ExfidOrigin())
{
return CMaxCard(1 /*ull*/);
}
// pass on max card of first child
return exprhdl.Pdprel(0)->Maxcard();
}
