// We peek at the table expression to compute the set of columns of the join
static SQuery _Join(ReaderBase f)
{
f.GetInt();
var st = f.buf.pos;
var d = SDict <int, (long, string)> .Empty;
var c = SDict <int, Serialisable> .Empty;
var nms = SDict <string, long> .Empty;
var left = f._Get() as SQuery ?? throw new StrongException("Query expected");
var outer = f.GetInt() == 1;
var joinType = (JoinType)f.GetInt();
var right = f._Get() as SQuery ?? throw new StrongException("Query expected");
var ab = left.Display.First();
var uses = SDict <long, long> .Empty;
if (joinType.HasFlag(JoinType.Named))
{
var n = f.GetInt();
for (var i = 0; i < n; i++)
{
uses += (f.GetLong(), f.GetLong());
}
}
var k = 0;
for (var lb = left.cpos.First(); ab != null && lb != null; ab = ab.Next(), lb = lb.Next())
{
var col = lb.Value;
var u = ab.Value.Item2;
d += (k, u);
c += (k, col.Item2);
nms += (u.Item2, u.Item1);
k++;
}
ab = right.Display.First();
for (var rb = right.cpos.First(); ab != null && rb != null; ab = ab.Next(), rb = rb.Next())
{
var u = ab.Value.Item2;
var n = u.Item2;
if (joinType == JoinType.Natural && nms.Contains(n))
{
continue;
}
if (uses.Contains(u.Item1))
{
continue;
}
var col = rb.Value;
d += (k, u);
c += (k, col.Item2);
k++;
}
f.buf.pos = st;
return(new SQuery(Types.STableExp, d, c));
}
public readonly SDict <long, long> uses; // Item1 is for RIGHT, Item2 for LEFT
public SJoin(ReaderBase f) : base(Types.STableExp, _Join(f))
{
left = f._Get() as SQuery ?? throw new StrongException("Query expected");
outer = f.GetInt() == 1;
joinType = (JoinType)f.GetInt();
right = f._Get() as SQuery ?? throw new StrongException("Query expected");
var n = f.GetInt();
var on = SList <SExpression> .Empty;
var us = SDict <long, long> .Empty;
var tr = (STransaction)f.db;
var lns = SDict <string, long> .Empty;
for (var b = left.Display.First(); b != null; b = b.Next())
{
lns += (b.Value.Item2.Item2, b.Value.Item2.Item1);
}
var rns = SDict <string, long> .Empty;
for (var b = right.Display.First(); b != null; b = b.Next())
{
var nm = b.Value.Item2.Item2;
if (joinType == JoinType.Natural && lns.Contains(nm))
{
us += (b.Value.Item2.Item1, lns[nm]);
}
rns += (nm, b.Value.Item2.Item1);
}
if (joinType.HasFlag(JoinType.Named))
{
for (var i = 0; i < n; i++)
{
var nm = tr.uids[f.GetLong()];
if (!(lns.Contains(nm) && rns.Contains(nm)))
{
throw new StrongException("name " + nm + " not present in Join");
}
us += (rns[nm], lns[nm]);
}
}
else if (!joinType.HasFlag(JoinType.Cross))
{
for (var i = 0; i < n; i++)
{
var e = f._Get() as SExpression
?? throw new StrongException("ON exp expected");
on += e;
}
}
ons = on;
uses = us;
f.context = this;
}
void CreateColumn(ReaderBase rdr)
{
var sc = (SColumn)rdr._Get();
var db = (STransaction)rdr.db;
sc = (SColumn)sc.Prepare(db, ((STable)db.objects[sc.table]).Names(db, SDict <long, long> .Empty));
var cn = db.role[sc.uid];
rdr.db = db.Install(new SColumn(db, sc.table, sc.dataType, sc.constraints), cn, db.curpos);
}
