private void EvaluateSingles(List <SqlBinaryExpression> list, List <ExpressionPlan> plans)
{
// The list of simple expression plans (lhs = single)
var simplePlanList = new List <SingleColumnPlan>();
// The list of complex function expression plans (lhs = expression)
var complexPlanList = new List <SingleColumnPlan>();
foreach (var expression in list)
{
// The single var
ObjectName singleVar;
SqlExpressionType op = expression.ExpressionType;
SqlExpression left = expression.Left, right = expression.Right;
if (expression.Right is SqlQuantifiedExpression)
{
singleVar = expression.Left.AsReferenceName();
if (singleVar != null)
{
plans.Add(new SimpleSelectPlan(this, singleVar, op, expression.Right));
}
else
{
singleVar = expression.Left.DiscoverReferences().First();
plans.Add(new ComplexSinglePlan(this, singleVar, expression));
}
}
else
{
singleVar = expression.Left.DiscoverReferences().FirstOrDefault();
if (singleVar == null)
{
// Reverse the expressions and the operator
var tempExp = left;
left = right;
right = tempExp;
op = op.Reverse();
singleVar = left.DiscoverReferences().First();
}
var tableSource = FindPlan(singleVar);
// Simple LHS?
var v = left.AsReferenceName();
if (v != null)
{
AddSingleColumnPlan(simplePlanList, tableSource, v, singleVar, new [] { left, right }, op);
}
else
{
// No, complex lhs
AddSingleColumnPlan(complexPlanList, tableSource, null, singleVar, new [] { left, right }, op);
}
}
}
plans.AddRange(simplePlanList.Select(plan => new SimpleSinglePlan(this, plan.UniqueName, plan.Expression)).Cast <ExpressionPlan>());
plans.AddRange(complexPlanList.Select(plan => new ComplexSinglePlan(this, plan.UniqueName, plan.Expression)).Cast <ExpressionPlan>());
}
private static IQueryPlanNode PlanForOrderBy(IQueryPlanNode plan, IList <SortColumn> orderBy, QueryExpressionFrom queryFrom, IList <SelectColumn> selectedColumns)
{
// Sort on the ORDER BY clause
if (orderBy.Count > 0)
{
int sz = orderBy.Count;
var orderList = new ObjectName[sz];
var ascendingList = new bool[sz];
var functionOrders = new List <SqlExpression>();
for (int i = 0; i < sz; ++i)
{
var column = orderBy[i];
SqlExpression exp = column.Expression;
ascendingList[i] = column.Ascending;
var v = exp.AsReferenceName();
if (v != null)
{
var newV = queryFrom.ResolveReference(v);
if (newV == null)
{
throw new InvalidOperationException(String.Format("Could not resolve ORDER BY column '{0}' in expression", v));
}
newV = ReplaceAliasedVariable(newV, selectedColumns);
orderList[i] = newV;
}
else
{
// Otherwise we must be ordering by an expression such as
// '0 - a'.
// Resolve the expression,
exp = exp.Prepare(queryFrom.ExpressionPreparer);
// Make sure we substitute any aliased columns in the order by
// columns.
exp = ReplaceAliasedVariables(exp, selectedColumns);
// The new ordering functions are called 'FUNCTIONTABLE.#ORDER-n'
// where n is the number of the ordering expression.
orderList[i] = new ObjectName(FunctionTableName, "#ORDER-" + functionOrders.Count);
functionOrders.Add(exp);
}
}
// If there are functional orderings,
// For this we must define a new FunctionTable with the expressions,
// then order by those columns, and then use another SubsetNode
// command node.
int fsz = functionOrders.Count;
if (fsz > 0)
{
var funs = new SqlExpression[fsz];
var fnames = new String[fsz];
for (int n = 0; n < fsz; ++n)
{
funs[n] = functionOrders[n];
fnames[n] = "#ORDER-" + n;
}
if (plan is SubsetNode)
{
// If the top plan is a SubsetNode then we use the
// information from it to create a new SubsetNode that
// doesn't include the functional orders we have attached here.
var topSubsetNode = (SubsetNode)plan;
var mappedNames = topSubsetNode.AliasColumnNames;
// Defines the sort functions
plan = new CreateFunctionsNode(plan, funs, fnames);
// Then plan the sort
plan = new SortNode(plan, orderList, ascendingList);
// Then plan the subset
plan = new SubsetNode(plan, mappedNames, mappedNames);
}
else
{
// Defines the sort functions
plan = new CreateFunctionsNode(plan, funs, fnames);
// Plan the sort
plan = new SortNode(plan, orderList, ascendingList);
}
}
else
{
// No functional orders so we only need to sort by the columns
// defined.
plan = new SortNode(plan, orderList, ascendingList);
}
}
return(plan);
}