/// <summary>
/// Analye EQUALS (=) node.
/// </summary>
/// <param name="equalsNode">node to analyze</param>
/// <param name="queryGraph">store relationships between stream properties</param>
/// <param name="isOuterJoin">if set to <c>true</c> [is outer join].</param>
internal static void AnalyzeEqualsNode(ExprEqualsNode equalsNode, QueryGraph queryGraph, bool isOuterJoin)
{
if ((equalsNode.ChildNodes[0] is ExprIdentNode) &&
(equalsNode.ChildNodes[1] is ExprIdentNode))
{
var identNodeLeft = (ExprIdentNode)equalsNode.ChildNodes[0];
var identNodeRight = (ExprIdentNode)equalsNode.ChildNodes[1];
if (identNodeLeft.StreamId != identNodeRight.StreamId)
{
queryGraph.AddStrictEquals(identNodeLeft.StreamId, identNodeLeft.ResolvedPropertyName, identNodeLeft,
identNodeRight.StreamId, identNodeRight.ResolvedPropertyName, identNodeRight);
}
return;
}
if (isOuterJoin) // outerjoins don't use constants or one-way expression-derived information to evaluate join
{
return;
}
// handle constant-compare or transformation case
var indexedStream = -1;
ExprIdentNode indexedPropExpr = null;
ExprNode exprNodeNoIdent = null;
if (equalsNode.ChildNodes[0] is ExprIdentNode)
{
indexedPropExpr = (ExprIdentNode)equalsNode.ChildNodes[0];
indexedStream = indexedPropExpr.StreamId;
exprNodeNoIdent = equalsNode.ChildNodes[1];
}
else if (equalsNode.ChildNodes[1] is ExprIdentNode)
{
indexedPropExpr = (ExprIdentNode)equalsNode.ChildNodes[1];
indexedStream = indexedPropExpr.StreamId;
exprNodeNoIdent = equalsNode.ChildNodes[0];
}
if (indexedStream == -1)
{
return; // require property of right/left side of equals
}
var eligibility = EligibilityUtil.VerifyInputStream(exprNodeNoIdent, indexedStream);
if (!eligibility.Eligibility.IsEligible())
{
return;
}
if (eligibility.Eligibility == Eligibility.REQUIRE_NONE)
{
queryGraph.AddUnkeyedExpression(indexedStream, indexedPropExpr, exprNodeNoIdent);
}
else
{
queryGraph.AddKeyedExpression(indexedStream, indexedPropExpr, eligibility.StreamNum.Value, exprNodeNoIdent);
}
}