protected void Init(RelNode value)
{
var equal = value.Heading.IsEqual(Heading);
var compat = equal || value.Heading.IsCompatible(Heading);
if (!compat)
{
throw Error.Fatal($"headings are not compatible: <{value.Heading}> and <{Heading}>");
}
var map = Heading.CreateMap(value.Heading);
Value = Rel.Create(value.Select(t => RelStatic.CreateByMap <T>(t, map)));
}
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;
}
// remove tuples that satisfy predicate
public void Delete(Func <T, bool> selfunc)
{
Value = Rel.Create(Value.Where(t => !selfunc(t)));
}
// update tuples that satisfy predicate
public void Update(Func <T, bool> selfunc, Func <T, T> upfunc)
{
Value = Rel.Create(Value.Select(t => selfunc(t) ? upfunc(t) : t));
}
// insert tuples, discard duplicates
public void Insert(RelValueST <T> value)
{
Value = Rel.Create(RelOpsST.Union(Value, value));
}
// relational assignment
public void Assign(RelValueST <T> value)
{
Value = Rel.Create(value);
}