internal static bool CanLift(SqlSource source, HashSet <SqlAlias> aliasesForLifting, HashSet <SqlExpression> liftedExpressions)
{
Visitor v = new Visitor(false, aliasesForLifting, liftedExpressions);
v.VisitSource(source);
return(v.canLiftAll);
}
private SqlSource PushSourceDown(SqlSource sqlSource, List <SqlColumn> cols)
{
SqlSelect ns = new SqlSelect(new SqlNop(cols[0].ClrType, cols[0].SqlType, sqlSource.SourceExpression), sqlSource, sqlSource.SourceExpression);
ns.Row.Columns.AddRange(cols);
return(new SqlAlias(ns));
}
private SqlJoin GetLeftOuterWithUnreferencedSingletonOnLeft(SqlSource source)
{
SqlAlias alias = source as SqlAlias;
if (alias != null)
{
SqlSelect select = alias.Node as SqlSelect;
if (select != null &&
select.Where == null &&
select.Top == null &&
select.GroupBy.Count == 0 &&
select.OrderBy.Count == 0)
{
return(this.GetLeftOuterWithUnreferencedSingletonOnLeft(select.From));
}
}
SqlJoin join = source as SqlJoin;
if (join == null || join.JoinType != SqlJoinType.LeftOuter)
{
return(null);
}
if (!this.IsSingletonSelect(join.Left))
{
return(null);
}
HashSet <SqlAlias> p = SqlGatherProducedAliases.Gather(join.Left);
HashSet <SqlAlias> c = SqlGatherConsumedAliases.Gather(join.Right);
if (p.Overlaps(c))
{
return(null);
}
return(join);
}
internal static List <List <SqlColumn> > Lift(SqlSource source, HashSet <SqlAlias> aliasesForLifting, HashSet <SqlExpression> liftedExpressions)
{
Visitor v = new Visitor(true, aliasesForLifting, liftedExpressions);
v.VisitSource(source);
return(v.lifted);
}
internal override SqlSource VisitJoin(SqlJoin join)
{
if (join.JoinType == SqlJoinType.CrossApply)
{
// Visit the left side as usual.
join.Left = this.VisitSource(join.Left);
// Visit the condition as usual.
join.Condition = this.VisitExpression(join.Condition);
// Visit the right, with the expressionSink set.
SelectScope s = expressionSink;
expressionSink = new SelectScope();
expressionSink.LeftProduction = SqlGatherProducedAliases.Gather(join.Left);
join.Right = this.VisitSource(join.Right);
// Were liftable expressions found?
SqlSource newSource = join;
foreach (List <SqlColumn> cols in expressionSink.Lifted)
{
newSource = PushSourceDown(newSource, cols);
}
expressionSink = s;
return(newSource);
}
return(base.VisitJoin(join));
}
static internal List <SqlColumn> GatherColumns(SqlSource source)
{
List <SqlColumn> columns = new List <SqlColumn>();
new Visitor(columns).Visit(source);
return(columns);
}
internal override SqlSource VisitJoin(SqlJoin join)
{
SqlSource left = this.VisitSource(join.Left);
SqlSource right = this.VisitSource(join.Right);
SqlExpression cond = (SqlExpression)this.Visit(join.Condition);
return(new SqlJoin(join.JoinType, left, right, cond, join.SourceExpression));
}
internal SqlJoin(SqlJoinType type, SqlSource left, SqlSource right, SqlExpression cond, Expression sourceExpression)
: base(SqlNodeType.Join, sourceExpression)
{
JoinType = type;
Left = left;
Right = right;
Condition = cond;
}
internal static SqlExpression Lift(SqlSource source, HashSet <SqlAlias> aliasesForLifting)
{
System.Diagnostics.Debug.Assert(source != null);
System.Diagnostics.Debug.Assert(aliasesForLifting != null);
Visitor v = new Visitor(true, aliasesForLifting, null);
v.VisitSource(source);
return(v.lifted);
}
internal static bool CanLift(SqlSource source, HashSet <SqlAlias> aliasesForLifting, HashSet <SqlExpression> liftedExpressions)
{
System.Diagnostics.Debug.Assert(source != null);
System.Diagnostics.Debug.Assert(aliasesForLifting != null);
Visitor v = new Visitor(false, aliasesForLifting, liftedExpressions);
v.VisitSource(source);
return(v.canLiftAll);
}
private bool HasTrivialSource(SqlSource node)
{
SqlAlias alias = node as SqlAlias;
if (alias == null)
{
return(false);
}
return(alias.Node is SqlSelect);
}
private bool HasTrivialSource(SqlSource node)
{
SqlJoin join = node as SqlJoin;
if (join != null)
{
return(this.HasTrivialSource(join.Left) &&
this.HasTrivialSource(join.Right));
}
return(node is SqlAlias);
}
internal SqlJoin MakeJoin(SqlJoinType joinType, SqlSource location, SqlAlias alias, SqlExpression condition, Expression source)
{
if (joinType == SqlJoinType.LeftOuter)
{
var sqlSelect = alias.Node as SqlSelect;
if (sqlSelect != null && sqlSelect.Selection != null && sqlSelect.Selection.NodeType != SqlNodeType.OptionalValue)
{
sqlSelect.Selection = new SqlOptionalValue(new SqlColumn("test", Unary(SqlNodeType.OuterJoinedValue, Value(typeof(int?), TypeProvider.From(typeof(int)), 1, false, source))), sqlSelect.Selection);
}
}
return(new SqlJoin(joinType, location, alias, condition, source));
}
internal override SqlSelect VisitSelect(SqlSelect select)
{
SqlSource from = this.VisitSource(select.From);
List <SqlExpression> gex = null;
if (select.GroupBy.Count > 0)
{
gex = new List <SqlExpression>(select.GroupBy.Count);
foreach (SqlExpression sqlExpr in select.GroupBy)
{
gex.Add((SqlExpression)this.Visit(sqlExpr));
}
}
SqlExpression having = (SqlExpression)this.Visit(select.Having);
List <SqlOrderExpression> lex = null;
if (select.OrderBy.Count > 0)
{
lex = new List <SqlOrderExpression>(select.OrderBy.Count);
foreach (SqlOrderExpression sox in select.OrderBy)
{
SqlOrderExpression nsox = new SqlOrderExpression(sox.OrderType, (SqlExpression)this.Visit(sox.Expression));
lex.Add(nsox);
}
}
SqlExpression top = (SqlExpression)this.Visit(select.Top);
SqlExpression where = (SqlExpression)this.Visit(select.Where);
SqlRow row = (SqlRow)this.Visit(select.Row);
SqlExpression selection = this.VisitExpression(select.Selection);
SqlSelect n = new SqlSelect(selection, from, select.SourceExpression);
if (gex != null)
{
n.GroupBy.AddRange(gex);
}
n.Having = having;
if (lex != null)
{
n.OrderBy.AddRange(lex);
}
n.OrderingType = select.OrderingType;
n.Row = row;
n.Top = top;
n.IsDistinct = select.IsDistinct;
n.IsPercent = select.IsPercent;
n.Where = where;
n.DoNotOutput = select.DoNotOutput;
return(n);
}
private SqlUnion GetUnion(SqlSource source)
{
SqlAlias alias = source as SqlAlias;
if (alias != null)
{
SqlUnion union = alias.Node as SqlUnion;
if (union != null)
{
return(union);
}
}
return(null);
}
internal override SqlSelect VisitSelect(SqlSelect select)
{
SqlSource from = VisitSource(select.From);
List <SqlExpression> list = null;
if (select.GroupBy.Count > 0)
{
list = new List <SqlExpression>(select.GroupBy.Count);
foreach (var item2 in select.GroupBy)
{
list.Add((SqlExpression)Visit(item2));
}
}
var having = (SqlExpression)Visit(select.Having);
List <SqlOrderExpression> list2 = null;
if (select.OrderBy.Count > 0)
{
list2 = new List <SqlOrderExpression>(select.OrderBy.Count);
foreach (var item3 in select.OrderBy)
{
var item = new SqlOrderExpression(item3.OrderType, (SqlExpression)Visit(item3.Expression));
list2.Add(item);
}
}
var top = (SqlExpression)Visit(select.Top);
var where = (SqlExpression)Visit(select.Where);
var row = (SqlRow)Visit(select.Row);
SqlExpression selection = VisitExpression(select.Selection);
var sqlSelect = new SqlSelect(selection, from, select.SourceExpression);
if (list != null)
{
sqlSelect.GroupBy.AddRange(list);
}
sqlSelect.Having = having;
if (list2 != null)
{
sqlSelect.OrderBy.AddRange(list2);
}
sqlSelect.OrderingType = select.OrderingType;
sqlSelect.Row = row;
sqlSelect.Top = top;
sqlSelect.IsDistinct = select.IsDistinct;
sqlSelect.IsPercent = select.IsPercent;
sqlSelect.Where = where;
sqlSelect.DoNotOutput = select.DoNotOutput;
return(sqlSelect);
}
internal override SqlSource VisitSource(SqlSource node)
{
node = (SqlSource)this.Visit(node);
SqlAlias alias = node as SqlAlias;
if (alias != null)
{
SqlSelect sel = alias.Node as SqlSelect;
if (sel != null && this.IsTrivialSelect(sel))
{
this.removedMap[alias] = alias;
node = sel.From;
}
}
return(node);
}
private void GetSelectionsBeforeJoin(SqlSource source, List <List <SqlColumn> > selections)
{
SqlJoin join = source as SqlJoin;
if (join != null)
{
return;
}
SqlAlias alias = source as SqlAlias;
if (alias != null)
{
SqlSelect select = alias.Node as SqlSelect;
if (select != null)
{
this.GetSelectionsBeforeJoin(select.From, selections);
selections.Add(select.Row.Columns);
}
}
}
private bool IsSingletonSelect(SqlSource source)
{
SqlAlias alias = source as SqlAlias;
if (alias == null)
{
return(false);
}
SqlSelect select = alias.Node as SqlSelect;
if (select == null)
{
return(false);
}
if (select.From != null)
{
return(false);
}
return(true);
}
private bool HasEmptySource(SqlSource node)
{
SqlAlias alias = node as SqlAlias;
if (alias == null)
{
return(false);
}
SqlSelect sel = alias.Node as SqlSelect;
if (sel == null)
{
return(false);
}
return(sel.Row.Columns.Count == 0 &&
sel.From == null &&
sel.Where == null &&
sel.GroupBy.Count == 0 &&
sel.Having == null &&
sel.OrderBy.Count == 0);
}
internal SqlJoin MakeJoin(SqlJoinType joinType, SqlSource location, SqlAlias alias, SqlExpression condition, Expression source)
{
// if the new item is on the right side of some outer join then fixup the projection to reflect that it can possibly be null
if (joinType == SqlJoinType.LeftOuter)
{
SqlSelect sel = alias.Node as SqlSelect;
if (sel != null && sel.Selection != null && sel.Selection.NodeType != SqlNodeType.OptionalValue)
{
// replace selection w/ optional + outer-joined-value
sel.Selection = new SqlOptionalValue(
new SqlColumn(
"test",
this.Unary(SqlNodeType.OuterJoinedValue,
this.Value(typeof(int?), this.typeProvider.From(typeof(int)), 1, false, source))
),
sel.Selection
);
}
}
return(new SqlJoin(joinType, location, alias, condition, source));
}
internal void BuildEqivalenceMap(SqlSource scope)
{
this.map = new Dictionary <SqlColumn, SqlColumn>();
this.Visit(scope);
}
internal virtual SqlSource VisitSource(SqlSource source)
{
return((SqlSource)this.Visit(source));
}
internal override SqlSource VisitSource(SqlSource source)
{
return(source);
}
internal override SqlSource VisitSource(SqlSource source)
{
source = base.VisitSource(source);
SqlJoin join = source as SqlJoin;
if (join != null)
{
if (join.JoinType == SqlJoinType.OuterApply)
{
// Reduce outer-apply into left-outer-join
HashSet <SqlAlias> leftProducedAliases = SqlGatherProducedAliases.Gather(join.Left);
HashSet <SqlExpression> liftedExpressions = new HashSet <SqlExpression>();
if (SqlPredicateLifter.CanLift(join.Right, leftProducedAliases, liftedExpressions) &&
SqlSelectionLifter.CanLift(join.Right, leftProducedAliases, liftedExpressions) &&
!SqlAliasDependencyChecker.IsDependent(join.Right, leftProducedAliases, liftedExpressions))
{
SqlExpression liftedPredicate = SqlPredicateLifter.Lift(join.Right, leftProducedAliases);
List <List <SqlColumn> > liftedSelections = SqlSelectionLifter.Lift(join.Right, leftProducedAliases, liftedExpressions);
join.JoinType = SqlJoinType.LeftOuter;
join.Condition = liftedPredicate;
if (liftedSelections != null)
{
foreach (List <SqlColumn> selection in liftedSelections)
{
source = this.PushSourceDown(source, selection);
}
}
}
else
{
this.AnnotateSqlIncompatibility(join, SqlProvider.ProviderMode.Sql2000);
}
}
else if (join.JoinType == SqlJoinType.CrossApply)
{
// reduce cross apply with special nested left-outer-join's into a single left-outer-join
//
// SELECT x.*, y.*
// FROM X
// CROSS APPLY (
// SELECT y.*
// FROM (
// SELECT ?
// )
// LEFT OUTER JOIN (
// SELECT y.* FROM Y
// ) AS y
//
// ==>
//
// SELECT x.*, y.*
// FROM X
// LEFT OUTER JOIN (
// SELECT y.* FROM Y
// )
SqlJoin leftOuter = this.GetLeftOuterWithUnreferencedSingletonOnLeft(join.Right);
if (leftOuter != null)
{
HashSet <SqlAlias> leftProducedAliases = SqlGatherProducedAliases.Gather(join.Left);
HashSet <SqlExpression> liftedExpressions = new HashSet <SqlExpression>();
if (SqlPredicateLifter.CanLift(leftOuter.Right, leftProducedAliases, liftedExpressions) &&
SqlSelectionLifter.CanLift(leftOuter.Right, leftProducedAliases, liftedExpressions) &&
!SqlAliasDependencyChecker.IsDependent(leftOuter.Right, leftProducedAliases, liftedExpressions)
)
{
SqlExpression liftedPredicate = SqlPredicateLifter.Lift(leftOuter.Right, leftProducedAliases);
List <List <SqlColumn> > liftedSelections = SqlSelectionLifter.Lift(leftOuter.Right, leftProducedAliases, liftedExpressions);
// add intermediate selections
this.GetSelectionsBeforeJoin(join.Right, liftedSelections);
// push down all selections
foreach (List <SqlColumn> selection in liftedSelections.Where(s => s.Count > 0))
{
source = this.PushSourceDown(source, selection);
}
join.JoinType = SqlJoinType.LeftOuter;
join.Condition = this.factory.AndAccumulate(leftOuter.Condition, liftedPredicate);
join.Right = leftOuter.Right;
}
else
{
this.AnnotateSqlIncompatibility(join, SqlProvider.ProviderMode.Sql2000);
}
}
}
// re-balance join tree of left-outer-joins to expose LOJ w/ leftside unreferenced
while (join.JoinType == SqlJoinType.LeftOuter)
{
// look for buried left-outer-joined-with-unreferenced singleton
SqlJoin leftLeftOuter = this.GetLeftOuterWithUnreferencedSingletonOnLeft(join.Left);
if (leftLeftOuter == null)
{
break;
}
List <List <SqlColumn> > liftedSelections = new List <List <SqlColumn> >();
// add intermediate selections
this.GetSelectionsBeforeJoin(join.Left, liftedSelections);
// push down all selections
foreach (List <SqlColumn> selection in liftedSelections)
{
source = this.PushSourceDown(source, selection);
}
// bubble this one up on-top of this 'join'.
SqlSource jRight = join.Right;
SqlExpression jCondition = join.Condition;
join.Left = leftLeftOuter.Left;
join.Right = leftLeftOuter;
join.Condition = leftLeftOuter.Condition;
leftLeftOuter.Left = leftLeftOuter.Right;
leftLeftOuter.Right = jRight;
leftLeftOuter.Condition = jCondition;
}
}
return(source);
}
