/// <summary>
/// Analye EQUALS (=) node.
/// </summary>
/// <param name="equalsNode">node to analyze</param>
/// <param name="queryGraph">store relationships between stream properties</param>
/// <param name="isOuterJoin">indicator for outer join</param>
protected internal static void AnalyzeEqualsNode(
ExprEqualsNode equalsNode,
QueryGraphForge 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);
}
}