public override SqlFragment Visit(DbNewInstanceExpression expression)
{
Debug.Assert(expression.ResultType.EdmType is CollectionType);
SelectStatement s = new SelectStatement();
ColumnFragment c = new ColumnFragment(null, null);
if (expression.Arguments.Count != 0)
c.Literal = (LiteralFragment)expression.Arguments[0].Accept(this);
else
c.Literal = new LiteralFragment("NULL");
c.ColumnAlias = "X";
s.Columns.Add(c);
return s;
}
private SelectStatement VisitInputExpressionEnsureSelect(DbExpression e, string name, TypeUsage type)
{
InputFragment fragment = VisitInputExpression(e, name, type);
if (fragment is SelectStatement) return (fragment as SelectStatement);
SelectStatement s = new SelectStatement();
// if the fragment is a union then it needs to be wrapped
if (fragment is UnionFragment)
(fragment as UnionFragment).Wrap(scope);
s.From = fragment;
return s;
}
private InputFragment WrapJoinInputIfNecessary(InputFragment fragment, bool isRightPart)
{
if (fragment is SelectStatement || fragment is UnionFragment)
{
fragment.Wrap(scope);
fragment.Scoped = true;
}
else if (fragment is JoinFragment && isRightPart)
{
SelectStatement select = new SelectStatement();
select.From = fragment;
select.Name = fragment.Name;
select.Wrap(scope);
return select;
}
return fragment;
}
public SelectStatement WrapIfNotCompatible(SelectStatement select, DbExpressionKind expressionKind)
{
if (select.IsCompatible(expressionKind)) return select;
SelectStatement newSelect = new SelectStatement();
select.Wrap(scope);
newSelect.From = select;
return newSelect;
}
public void Visit(SelectStatement f)
{
}
/// <summary>
/// If input sqlFragment is a group by structure, is flattened to remove some nested correlation queries.
/// </summary>
/// <param name="input"></param>
/// <returns></returns>
private SqlFragment TryFlatteningGroupBy(SqlFragment input)
{
SelectStatement select = null;
SelectStatement tmpFrag = null, tmpFrag2 = null, tmpFrag3 = null;
InputFragment table = null;
string objName = null, colName = null, queryName = null;
// First part assert is a kind-of structure we are looking for
tmpFrag = input as SelectStatement;
if (tmpFrag == null) goto NoChanges;
tmpFrag = ( tmpFrag ).From as SelectStatement;
if (tmpFrag == null) goto NoChanges;
queryName = tmpFrag.Name;
if (tmpFrag.Columns.Count < 2) goto NoChanges;
if (!(tmpFrag.Columns[0] is ColumnFragment)) goto NoChanges;
colName = objName = (tmpFrag.Columns[0] as ColumnFragment).ActualColumnName;
tmpFrag2 = tmpFrag.From as SelectStatement;
if (tmpFrag2 == null) goto NoChanges;
if (tmpFrag2.Columns.Count < 1 || !(tmpFrag2.Columns[0] is ColumnFragment)) goto NoChanges;
if (string.CompareOrdinal(objName, tmpFrag2.Columns[0].ActualColumnName) != 0) goto NoChanges;
if (tmpFrag.Columns[1].Literal == null ) goto NoChanges;
tmpFrag2 = tmpFrag.Columns[1].Literal as SelectStatement;
if (tmpFrag2 == null) goto NoChanges;
if ((tmpFrag2.Columns.Count != 1) || !(tmpFrag2.Columns[0].Literal != null)) goto NoChanges;
tmpFrag3 = tmpFrag2.From as SelectStatement;
if (tmpFrag3 == null) goto NoChanges;
table = tmpFrag3.From as InputFragment;
if (table == null) goto NoChanges;
FunctionFragment func = tmpFrag2.Columns[0].Literal as FunctionFragment;
if( tmpFrag3.Columns.Count != 1 || !( tmpFrag3.Columns[ 0 ] is ColumnFragment )) goto NoChanges;
if (func == null) goto NoChanges;
// Yes it is the kind-of type we like, then optimize it
select = new SelectStatement(this);
table.Name = null;
string tableName = null;
TableFragment t = tmpFrag3.From as TableFragment;
if (t == null)
tableName = tmpFrag3.Columns[0].TableName;
else
tableName = t.Table;
select.From = table;
select.Columns.Add(new ColumnFragment(tableName, colName));
select.Columns.Add(new ColumnFragment(tableName, "C0")
{
ColumnAlias = "C1",
Literal = new FunctionFragment() {
Argument = new ColumnFragment(tableName, tmpFrag3.Columns[0].ActualColumnName),
Distinct = tmpFrag3.IsDistinct,
Name = func.Name
}
});
select.Wrap(null);
select.Name = queryName;
select.AddGroupBy(select.Columns[0]);
(input as SelectStatement).From = select;
NoChanges:
return input;
}
public override SqlFragment Visit(DbApplyExpression expression)
{
DbExpressionBinding inputBinding = expression.Input;
InputFragment input = VisitInputExpression(inputBinding.Expression, inputBinding.VariableName, inputBinding.VariableType);
DbExpressionBinding applyBinding = expression.Apply;
InputFragment apply = VisitInputExpression(applyBinding.Expression, applyBinding.VariableName, applyBinding.VariableType);
SelectStatement select = new SelectStatement(this);
bool isInputSelect = false;
if (!(input is TableFragment))
{
input.Wrap(scope);
isInputSelect = true;
}
apply.Wrap(scope);
select.From = input;
select.Wrap(scope);
if (apply is SelectStatement)
{
SelectStatement applySel = apply as SelectStatement;
foreach (ColumnFragment f in applySel.Columns)
{
SelectStatement newColSelect = new SelectStatement(this);
newColSelect.From = applySel.From;
newColSelect.Where = applySel.Where;
if (isInputSelect)
{
VisitAndReplaceTableName(newColSelect.Where, (input as SelectStatement).From.Name, input.Name);
}
newColSelect.Limit = applySel.Limit;
newColSelect.Columns.Add( f );
newColSelect.Wrap(scope);
scope.Add(applySel.From.Name, applySel.From);
ColumnFragment newCol = new ColumnFragment(apply.Name, f.ColumnName);
newCol.Literal = newColSelect;
newCol.PushInput(newCol.ColumnName);
newCol.PushInput(apply.Name);
select.AddColumn( newCol, scope);
if (string.IsNullOrEmpty(newCol.ColumnAlias))
{
newColSelect.Name = newCol.ColumnName;
newCol.ColumnAlias = newCol.ColumnName;
}
scope.Remove(newColSelect);
}
scope.Remove(applySel.From);
scope.Remove(apply);
}
return select;
}
public override SqlFragment Visit(DbApplyExpression expression)
{
DbExpressionBinding inputBinding = expression.Input;
InputFragment input = VisitInputExpression(inputBinding.Expression, inputBinding.VariableName, inputBinding.VariableType);
DbExpressionBinding applyBinding = expression.Apply;
InputFragment apply = VisitInputExpression(applyBinding.Expression, applyBinding.VariableName, applyBinding.VariableType);
SelectStatement select = new SelectStatement(this);
bool isInputSelect = false;
if (!(input is TableFragment))
{
input.Wrap(scope);
isInputSelect = true;
}
apply.Wrap(scope);
select.From = input;
select.Wrap(scope);
if (apply is SelectStatement)
{
SelectStatement applySel = apply as SelectStatement;
foreach (ColumnFragment f in applySel.Columns)
{
SelectStatement newColSelect = new SelectStatement(this);
newColSelect.From = applySel.From;
newColSelect.Where = applySel.Where;
if (isInputSelect)
{
VisitAndReplaceTableName(newColSelect.Where, (input as SelectStatement).From.Name, input.Name, null);
}
newColSelect.Limit = applySel.Limit;
newColSelect.OrderBy = applySel.OrderBy;
newColSelect.Skip = applySel.Skip;
newColSelect.GroupBy = applySel.GroupBy;
newColSelect.IsDistinct = applySel.IsDistinct;
newColSelect.Columns.Add(f);
newColSelect.Wrap(scope);
scope.Add(applySel.From.Name, applySel.From);
ColumnFragment newCol = new ColumnFragment(apply.Name, f.ColumnName);
newCol.Literal = newColSelect;
newCol.PushInput(newCol.ColumnName);
newCol.PushInput(apply.Name);
select.AddColumn(newCol, scope);
if (string.IsNullOrEmpty(newCol.ColumnAlias))
{
newColSelect.Name = newCol.ColumnName;
newCol.ColumnAlias = newCol.ColumnName;
}
scope.Remove(newColSelect);
}
scope.Remove(applySel.From);
scope.Remove(apply);
}
else if (apply is UnionFragment)
{
UnionFragment uf = apply as UnionFragment;
if (uf.Left == null || uf.Right == null)
throw new Exception("Union fragment is not properly formed.");
var left = uf.Left as SelectStatement;
var right = uf.Right as SelectStatement;
if (left == null || right == null)
throw new NotImplementedException();
var whereleft = left.Where as BinaryFragment;
var whereright = right.Where as BinaryFragment;
if (whereleft == null || whereright == null)
throw new NotImplementedException();
LiteralFragment literalFragmentWhere = null;
//checking where left
if (whereleft.Left is ColumnFragment && whereleft.Right is ColumnFragment)
{
// we replace the where part for a dummy one
if (whereright.Left is ColumnFragment && whereright.Right is ColumnFragment)
{
literalFragmentWhere = new LiteralFragment("1 = 1");
}
}
if (literalFragmentWhere == null)
throw new NotImplementedException();
var leftouterjoin = new JoinFragment();
leftouterjoin.JoinType = Metadata.GetOperator(DbExpressionKind.LeftOuterJoin);
leftouterjoin.Name = apply.Name;
// validating that column fragment on the left matches the name
// for the input fragment
var leftColumnFragment = whereleft.Left as ColumnFragment;
if (leftColumnFragment == null)
throw new NotImplementedException();
if (!leftColumnFragment.TableName.Equals(input.Name))
new NotImplementedException();
var conditionJoin = new BinaryFragment();
conditionJoin.Left = whereleft.Left;
//update to the new reference
var newColumnFragment = whereright.Right as ColumnFragment;
if (newColumnFragment != null)
{
newColumnFragment.TableName = uf.Name;
}
conditionJoin.Right = newColumnFragment;
conditionJoin.Operator = whereleft.Operator;
leftouterjoin.Condition = conditionJoin;
(uf.Left as SelectStatement).Where = literalFragmentWhere;
(uf.Right as SelectStatement).Where = literalFragmentWhere;
leftouterjoin.Left = input;
leftouterjoin.Right = uf;
return leftouterjoin;
}
return select;
}
List <ColumnFragment> GetDefaultColumnsForFragment(InputFragment input)
{
List <ColumnFragment> columns = new List <ColumnFragment>();
if (input is TableFragment)
{
return(GetDefaultColumnsForTable(input as TableFragment));
}
else if (input is JoinFragment || input is UnionFragment)
{
Debug.Assert(input.Left != null);
if (input is UnionFragment)
{
generator.Ops.Push(OpType.Union);
}
columns = GetDefaultColumnsForFragment(input.Left);
if (input is JoinFragment && input.Right != null)
{
List <ColumnFragment> right = GetDefaultColumnsForFragment(input.Right);
columns.AddRange(right);
}
if (input is UnionFragment)
{
generator.Ops.Pop();
}
}
else if (input is SelectStatement)
{
SelectStatement select = input as SelectStatement;
foreach (ColumnFragment cf in select.Columns)
{
ColumnFragment newColumn = new ColumnFragment(cf.TableName,
string.IsNullOrEmpty(cf.ColumnAlias) ? cf.ActualColumnName : cf.ColumnAlias
);
if (generator.GetTopOp() == OpType.Join)
{
newColumn.ColumnAlias = cf.ColumnAlias;
newColumn.PushInput(cf.ColumnName);
if (cf.TableName != null)
{
newColumn.PushInput(cf.TableName);
}
}
else
{
newColumn.PushInput(cf.ActualColumnName);
if (cf.TableName != null && cf.ColumnAlias == null)
{
newColumn.PushInput(cf.TableName);
}
}
if (select.Name != null)
{
newColumn.PushInput(select.Name); // add the scope
}
columns.Add(newColumn);
}
return(columns);
}
else
{
throw new NotImplementedException();
}
if (!String.IsNullOrEmpty(input.Name) && input.Name != From.Name)
{
foreach (ColumnFragment c in columns)
{
c.PushInput(input.Name);
}
}
return(columns);
}
