internal override bool SelectTable(string table)
{
_table = table;
var path = GetPath();
if (!File.Exists(path))
{
return(false);
}
using (var rdr = new TextFieldParser(path)
{
TextFieldType = FieldType.Delimited,
Delimiters = new string[] { "," },
}) {
var row = rdr.ReadFields();
if (_hasid)
{
row = (new string[] { "Id:number" })
.Concat(row).ToArray();
}
var fields = row.Select(r => new CommonField {
Name = r, CType = CommonType.Text
}).ToArray();
Heading = CommonHeading.Create(fields);
}
return(true);
}
// remove tuples that satisfy predicate
public void Delete(string heading, Func <Tup, bool> selfunc)
{
var head = CommonHeading.Create(heading);
var map = head.CreateMap(Heading);
Value = new RelValue(Heading, Value.Where(t => !selfunc(RelStatic.CreateByMap <Tup>(t, map))));
}
static IEnumerable <TupBase> While(CommonHeading heading, IEnumerable <TupBase> body, Func <RelNode, RelNode> func)
{
var stack = new Stack <TupBase>(body);
var hash = new HashSet <TupBase>();
while (stack.Count > 0)
{
var top = stack.Pop();
if (!hash.Contains(top))
{
hash.Add(top);
var result = func(new WrapperNode(heading, Enumerable.Repeat(top, 1)));
var eq = result.Heading.IsEqual(heading);
var map = heading.CreateMap(result.Heading);
if (result.Heading.Degree != heading.Degree ||
map.Any(x => x < 0))
{
throw Error.Fatal("While", $"heading mismatch: {result.Heading} {heading}");
}
// convert compatible if needed
foreach (var t in result)
{
stack.Push(eq ? t : RelStatic.CreateByMap <Tup>(t, map));
}
}
}
return(hash);
}
public RenameNode(RelNode source, CommonHeading nodeheading)
{
_source = source;
_nodeheading = nodeheading;
_map = _nodeheading.CreateMap(_source.Heading);
if (!(_map.Length == 2 && _map[0] >= 0 && _map[1] < 0))
{
throw Error.Fatal("Rename", "heading is invalid");
}
Heading = _source.Heading.Rename(_nodeheading[0], _nodeheading[1]);
}
// update tuples that satisfy predicate
public void Update(string heading, Func <Tup, bool> selfunc, object newvalue)
{
// map for selection tuple
var head1 = CommonHeading.Create(heading);
var map1 = head1.CreateMap(Heading);
// map for replace tuple
var head2 = Heading.Remove(head1.Fields.Last()).Append(CommonField.Empty);
var map2 = head2.CreateMap(Heading);
Value = new RelValue(Heading, Value.Select(t => selfunc(RelStatic.CreateByMap <Tup>(t, map1))
? RelStatic.CreateByMap <Tup>(t, map2, newvalue) : t));
}
// select the schema as the current table
bool SelectSchema()
{
_table = null;
var schema = GetSchema();
var scols = schema.Columns;
var fields = Enumerable.Range(0, scols.Count)
.Select(x => new CommonField {
Name = scols[x].ColumnName, CType = CommonConverter.TypeToCommon(scols[x].DataType)
}).ToArray();
Heading = CommonHeading.Create(fields);
return(true);
}
public RestrictNode(RelNode source, CommonHeading nodeheading, RelFuncBase func)
{
_source = source;
_restheading = nodeheading;
_restfunc = func;
Heading = _source.Heading;
_restmap = _restheading.CreateMap(Heading);
if (_restmap.Any(x => x < 0))
{
throw Error.Fatal("Restrict", "heading has unknown attribute");
}
}
//--- impl
// reflection hack to get heading value from tuple
// TODO: is this the best way to handle heading not found?
internal static CommonHeading GetHeading(Type ttype)
{
var prop = ttype.GetField("Heading");
if (prop == null)
{
return(CommonHeading.Empty);
}
var heading = (string)prop.GetValue(null);
if (heading == null)
{
return(CommonHeading.Empty);
}
return(CommonHeading.Create(heading)); // TODO: add types
}
public ProjectNode(RelNode source, CommonHeading nodeheading, bool isremove = false)
{
_source = source;
var _nodeheading = nodeheading;
Heading = (isremove) ? _source.Heading.Minus(_nodeheading) : _nodeheading;
_map = Heading.CreateMap(_source.Heading);
if (Heading.Degree > _source.Heading.Degree)
{
throw Error.Fatal("Project", "too many attributes");
}
if (_map.Any(x => x < 0))
{
throw Error.Fatal("Project", "heading does not match");
}
}
public AggregateNode(RelNode source, CommonHeading nodeheading, RelFuncBase func, object initial = null)
{
_source = source;
_heading = nodeheading;
_func = func;
_initial = initial;
Heading = _source.Heading.Rename(_heading[0], _heading[1]);
_vmap = _heading.CreateMap(_source.Heading);
_jhead = _source.Heading.Minus(_heading);
_jmap1 = _jhead.CreateMap(_source.Heading);
_jmap2 = Heading.CreateMap(_jhead);
if (!(_heading.Degree == 2 && _jmap2.Length == Heading.Degree))
{
throw Error.Fatal("Aggregate", "heading is not valid");
}
}
public UngroupNode(RelNode source, UngroupingOp op, CommonHeading nodeheading)
{
_source = source;
_op = op;
_nodeheading = nodeheading;
_nodemap = _nodeheading.CreateMap(_source.Heading);
if (!(_nodemap.Length == 1 && _nodemap[0] >= 0))
{
throw Error.Fatal("Ungroup", "heading is not valid");
}
// on output replace one field by the TVA/RVA
Heading = _source.Heading.Remove(_nodeheading[0]).Append(_nodeheading[0].Fields);
//
var tupheading = CommonHeading.Create(_nodeheading[0].Fields);
_map1 = Heading.CreateMap(_source.Heading);
_map2 = Heading.CreateMap(tupheading);
}
public GroupNode(RelNode source, GroupingOp op, CommonHeading nodeheading)
{
_source = source;
_op = op;
_nodeheading = nodeheading;
// inner tuple(s) for TVA or RVA
var tupheading = _nodeheading.Remove(_nodeheading.Fields.Last());
_tmap = tupheading.CreateMap(_source.Heading);
// outer fields used as key for index
var keyheading = _source.Heading.Minus(tupheading);
_kmap = keyheading.CreateMap(_source.Heading);
// final result with new field appended
Heading = keyheading.Append(new CommonField(_nodeheading.Fields.Last().Name,
(_op == GroupingOp.Group) ? CommonType.Table : CommonType.Row, tupheading.Fields));
_map = Heading.CreateMap(keyheading);
if (!(_tmap.All(x => x >= 0) && _kmap.All(x => x >= 0) && _map.Last() < 0))
{
throw Error.Fatal("Group", "heading is not valid");
}
}
public ExtendNode(RelNode source, CommonHeading nodeheading, RelFuncBase func)
{
_source = source;
_nodeheading = nodeheading;
_func = func;
Heading = CommonHeading.Create(_source.Heading.Fields.Union(_nodeheading.Fields));
// get the argument fields
_argheading = CommonHeading.Create(_nodeheading.Fields.Take(_nodeheading.Fields.Length - 1));
_argmap = _argheading.CreateMap(_source.Heading);
// last field can extend or replace, remove name but retain place
var outh = Heading.Rename(_nodeheading.Fields.Last(), CommonField.Empty);
_outmap = Heading.CreateMap(outh);
if (_argmap.Any(x => x < 0))
{
throw Error.Fatal("Extend", "heading has unknown attribute");
}
if (_outmap.Count(x => x < 0) != 1)
{
throw Error.Fatal("Extend", "invalid heading, invalid new attribute"); // any use?
}
}
// Generic input
internal override bool SelectTable(string table)
{
//Logger.WriteLine(2, "Sql Peek '{0}'", table);
if (table == null)
{
return(SelectSchema());
}
using (var reader = Open(table)) {
if (reader == null)
{
return(false);
}
_table = table;
//Logger.WriteLine(3, "Table {0} fields {1}", table, String.Join(",", s));
var fields = Enumerable.Range(0, reader.FieldCount)
.Where(x => _convdict.ContainsKey(reader.GetDataTypeName(x)))
.Select(x => new CommonField {
Name = reader.GetName(x), CType = _convdict[reader.GetDataTypeName(x)]
}).ToArray();
Heading = CommonHeading.Create(fields);
}
Close();
return(true);
}
public RelVarST(RelNode value)
{
Heading = RelBaseST <T> .Heading;
Init(value);
}
public RelVarST(RelValueST <T> tuples)
{
Value = Rel.Create(tuples);
Heading = RelBaseST <T> .Heading;
}
public RelVarST()
{
Value = Rel.Create(new T[0]);
Heading = RelBaseST <T> .Heading;
}
// Construct a node from a stream
public static RelNode Create(string heading, IEnumerable <Tup> source)
{
return(new WrapperNode(CommonHeading.Create(heading), source));
}
public WrapperNode(CommonHeading heading, IEnumerable <TupBase> source)
{
_source = source;
Heading = heading;
}
// create new relation value from body as enumerable
public RelValue(CommonHeading heading, IEnumerable <Tup> body)
{
Heading = heading;
_body = new HashSet <Tup>(body);
}
// create new relation value from body as set
public RelValue(CommonHeading heading, HashSet <Tup> body)
{
Heading = heading;
_body = body;
}
// Construct a node from literal data
public static RelNode Data(string heading, params Tup[] source)
{
return(new WrapperNode(CommonHeading.Create(heading), source));
}
//--- ctor
// set up heading here when relation not instantiated but used to get heading
static RelBaseST()
{
Heading = GetHeading(typeof(T));
}
public RelBaseST()
{
Heading = GetHeading(typeof(T));
_body = new HashSet <T>();
}
// Allow heading to be set as a string "name:type,name:type..."
internal void SetHeading(string heading)
{
Heading = CommonHeading.Create(heading);
}
public string Format(CommonHeading heading)
{
return(Enumerable.Range(0, Values.Length)
.Select(x => heading[x].Format(Values[x]))
.Join(", "));
}
