internal override SqlRowNumber VisitRowNumber(SqlRowNumber rowNumber)
{
if(rowNumber.OrderBy.Count > 0) return rowNumber;
SqlDuplicator dup = new SqlDuplicator(true);
List<SqlOrderExpression> orderBy = new List<SqlOrderExpression>();
List<SqlOrderExpression> existingOrders = new List<SqlOrderExpression>();
if(this.rowNumberOrders != null && this.rowNumberOrders.Count != 0)
{
existingOrders = new List<SqlOrderExpression>(this.rowNumberOrders);
}
else if(this.orders != null)
{
existingOrders = new List<SqlOrderExpression>(this.orders);
}
foreach(SqlOrderExpression expr in existingOrders)
{
if(!expr.Expression.IsConstantColumn)
{
orderBy.Add(expr);
if(this.rowNumberOrders != null)
{
this.rowNumberOrders.Remove(expr);
}
if(this.orders != null)
{
this.orders.Remove(expr);
}
}
}
rowNumber.OrderBy.Clear();
if(orderBy.Count == 0)
{
List<SqlColumn> columns = SqlGatherColumnsProduced.GatherColumns(this.currentSelect.From);
foreach(SqlColumn col in columns)
{
if(col.Expression.SqlType.IsOrderable)
{
orderBy.Add(new SqlOrderExpression(SqlOrderType.Ascending, new SqlColumnRef(col)));
}
}
if(orderBy.Count == 0)
{
// insert simple column
SqlColumn col =
new SqlColumn(
"rowNumberOrder",
sql.Value(typeof(int), this.typeProvider.From(typeof(int)), 1, false, rowNumber.SourceExpression)
);
this.PushDown(col);
orderBy.Add(new SqlOrderExpression(SqlOrderType.Ascending, new SqlColumnRef(col)));
}
}
foreach(SqlOrderExpression sox in orderBy)
{
rowNumber.OrderBy.Add(new SqlOrderExpression(sox.OrderType, (SqlExpression)dup.Duplicate(sox.Expression)));
}
return rowNumber;
}
internal override SqlSelect VisitSelect(SqlSelect select)
{
bool saveTop = this.topSelect;
bool savePK = this.addPrimaryKeys;
SqlSelect saveSelect = this.currentSelect;
this.currentSelect = select;
if(select.OrderingType == SqlOrderingType.Always)
{
this.addPrimaryKeys = true;
}
this.topSelect = false;
// can't forward ordering information through a group-by
if(select.GroupBy.Count > 0)
{
this.Visit(select.From);
this.orders = null;
}
else
{
this.Visit(select.From);
}
if(select.OrderBy.Count > 0)
{
this.PrependOrderExpressions(select.OrderBy);
}
List<SqlOrderExpression> save = this.orders;
this.orders = null;
this.rowNumberOrders = save; // lest orders be null when we need info
/* do all the lower level stuff */
select.Where = this.VisitExpression(select.Where);
for(int i = 0, n = select.GroupBy.Count; i < n; i++)
{
select.GroupBy[i] = this.VisitExpression(select.GroupBy[i]);
}
select.Having = this.VisitExpression(select.Having);
for(int i = 0, n = select.OrderBy.Count; i < n; i++)
{
select.OrderBy[i].Expression = this.VisitExpression(select.OrderBy[i].Expression);
}
select.Top = this.VisitExpression(select.Top);
select.Selection = this.VisitExpression(select.Selection);
select.Row = (SqlRow)this.Visit(select.Row);
this.topSelect = saveTop;
this.addPrimaryKeys = savePK;
this.orders = save;
// all ordering is blocked for this layer and above
if(select.OrderingType == SqlOrderingType.Blocked)
{
this.orders = null;
}
// rebuild orderby expressions, provided this select doesn't contain a SqlRowNumber
// otherwise, replace the orderby with a reference to that column
select.OrderBy.Clear();
var rowNumberChecker = new SqlRowNumberChecker();
if(rowNumberChecker.HasRowNumber(select) && rowNumberChecker.RowNumberColumn != null)
{
select.Row.Columns.Remove(rowNumberChecker.RowNumberColumn);
this.PushDown(rowNumberChecker.RowNumberColumn);
this.Orders.Add(new SqlOrderExpression(SqlOrderType.Ascending, new SqlColumnRef(rowNumberChecker.RowNumberColumn)));
}
if((this.topSelect || select.Top != null) && select.OrderingType != SqlOrderingType.Never && this.orders != null)
{
this.orders = new HashSet<SqlOrderExpression>(this.orders).ToList();
SqlDuplicator dup = new SqlDuplicator(true);
foreach(SqlOrderExpression sox in this.orders)
{
select.OrderBy.Add(new SqlOrderExpression(sox.OrderType, (SqlExpression)dup.Duplicate(sox.Expression)));
}
}
this.currentSelect = saveSelect;
return select;
}
private SqlExpression MakeCoalesce(SqlExpression left, SqlExpression right, Type resultType)
{
CompensateForLowerPrecedenceOfDateType(ref left, ref right); // DevDiv 176874
if(TypeSystem.IsSimpleType(resultType))
{
return _nodeFactory.Binary(SqlNodeType.Coalesce, left, right, resultType);
}
else
{
List<SqlWhen> whens = new List<SqlWhen>(1);
whens.Add(new SqlWhen(_nodeFactory.Unary(SqlNodeType.IsNull, left, left.SourceExpression), right));
SqlDuplicator dup = new SqlDuplicator(true);
return _nodeFactory.SearchedCase(whens.ToArray(), (SqlExpression)dup.Duplicate(left), _dominatingExpression);
}
}
private SqlNode VisitGroupBy(Expression sequence, LambdaExpression keyLambda, LambdaExpression elemLambda, LambdaExpression resultSelector)
{
// Convert seq.Group(elem, key) into
//
// SELECT s.key, MULTISET(select s2.elem from seq AS s2 where s.key == s2.key)
// FROM seq AS s
//
// where key and elem can be either simple scalars or object constructions
//
SqlSelect seq = this.VisitSequence(sequence);
seq = this.LockSelect(seq);
SqlAlias seqAlias = new SqlAlias(seq);
SqlAliasRef seqAliasRef = new SqlAliasRef(seqAlias);
// evaluate the key expression relative to original sequence
_parameterExpressionToSqlExpression[keyLambda.Parameters[0]] = seqAliasRef;
SqlExpression keyExpr = this.VisitExpression(keyLambda.Body);
// make a duplicate of the original sequence to use as a foundation of our group multiset
SqlDuplicator sd = new SqlDuplicator();
SqlSelect selDup = (SqlSelect)sd.Duplicate(seq);
// rebind key in relative to the duplicate sequence
SqlAlias selDupAlias = new SqlAlias(selDup);
SqlAliasRef selDupRef = new SqlAliasRef(selDupAlias);
_parameterExpressionToSqlExpression[keyLambda.Parameters[0]] = selDupRef;
SqlExpression keyDup = this.VisitExpression(keyLambda.Body);
SqlExpression elemExpr = null;
SqlExpression elemOnGroupSource = null;
if(elemLambda != null)
{
// evaluate element expression relative to the duplicate sequence
_parameterExpressionToSqlExpression[elemLambda.Parameters[0]] = selDupRef;
elemExpr = this.VisitExpression(elemLambda.Body);
// evaluate element expression relative to original sequence
_parameterExpressionToSqlExpression[elemLambda.Parameters[0]] = seqAliasRef;
elemOnGroupSource = this.VisitExpression(elemLambda.Body);
}
else
{
// no elem expression supplied, so just use an alias ref to the duplicate sequence.
// this will resolve to whatever was being produced by the sequence
elemExpr = selDupRef;
elemOnGroupSource = seqAliasRef;
}
// Make a sub expression out of the key. This will allow a single definition of the
// expression to be shared at multiple points in the tree (via SqlSharedExpressionRef's)
SqlSharedExpression keySubExpr = new SqlSharedExpression(keyExpr);
keyExpr = new SqlSharedExpressionRef(keySubExpr);
// construct the select clause that picks out the elements (this may be redundant...)
SqlSelect selElem = new SqlSelect(elemExpr, selDupAlias, _dominatingExpression);
selElem.Where = _nodeFactory.Binary(SqlNodeType.EQ2V, keyExpr, keyDup);
// Finally, make the MULTISET node. this will be used as part of the final select
SqlSubSelect ss = _nodeFactory.SubSelect(SqlNodeType.Multiset, selElem);
// add a layer to the original sequence before applying the actual group-by clause
SqlSelect gsel = new SqlSelect(new SqlSharedExpressionRef(keySubExpr), seqAlias, _dominatingExpression);
gsel.GroupBy.Add(keySubExpr);
SqlAlias gselAlias = new SqlAlias(gsel);
SqlSelect result = null;
if(resultSelector != null)
{
// Create final select to include construction of group multiset
// select new Grouping { Key = key, Group = Multiset(select elem from seq where match) } from ...
Type elementType = typeof(IGrouping<,>).MakeGenericType(keyExpr.ClrType, elemExpr.ClrType);
SqlExpression keyGroup = new SqlGrouping(elementType, _typeProvider.From(elementType), keyExpr, ss, _dominatingExpression);
SqlSelect keyGroupSel = new SqlSelect(keyGroup, gselAlias, _dominatingExpression);
SqlAlias kgAlias = new SqlAlias(keyGroupSel);
SqlAliasRef kgAliasRef = new SqlAliasRef(kgAlias);
_parameterExpressionToSqlExpression[resultSelector.Parameters[0]] = _nodeFactory.Member(kgAliasRef, elementType.GetProperty("Key"));
_parameterExpressionToSqlExpression[resultSelector.Parameters[1]] = kgAliasRef;
// remember the select that has the actual group (for optimizing aggregates later)
_sqlNodeToGroupInfo[kgAliasRef] = new GroupInfo { SelectWithGroup = gsel, ElementOnGroupSource = elemOnGroupSource };
SqlExpression resultExpr = this.VisitExpression(resultSelector.Body);
result = new SqlSelect(resultExpr, kgAlias, _dominatingExpression);
// remember the select that has the actual group (for optimizing aggregates later)
_sqlNodeToGroupInfo[resultExpr] = new GroupInfo { SelectWithGroup = gsel, ElementOnGroupSource = elemOnGroupSource };
}
else
{
// Create final select to include construction of group multiset
// select new Grouping { Key = key, Group = Multiset(select elem from seq where match) } from ...
Type elementType = typeof(IGrouping<,>).MakeGenericType(keyExpr.ClrType, elemExpr.ClrType);
SqlExpression resultExpr = new SqlGrouping(elementType, _typeProvider.From(elementType), keyExpr, ss, _dominatingExpression);
result = new SqlSelect(resultExpr, gselAlias, _dominatingExpression);
// remember the select that has the actual group (for optimizing aggregates later)
_sqlNodeToGroupInfo[resultExpr] = new GroupInfo { SelectWithGroup = gsel, ElementOnGroupSource = elemOnGroupSource };
}
return result;
}
private SqlNode VisitParameter(ParameterExpression p)
{
SqlExpression sqlExpr;
if(_parameterExpressionToSqlExpression.TryGetValue(p, out sqlExpr))
return sqlExpr;
Expression expr;
if(_parameterExpressionToExpression.TryGetValue(p, out expr))
return this.Visit(expr);
SqlNode nodeToDup;
if(_parameterExpressionToSqlNode.TryGetValue(p, out nodeToDup))
{
SqlDuplicator duplicator = new SqlDuplicator(true);
return duplicator.Duplicate(nodeToDup);
}
throw Error.ParameterNotInScope(p.Name);
}