static void ResolveAlias(Parse parse, ExprList list, int colId, Expr expr, string type, int subqueries)
{
Debug.Assert(colId >= 0 && colId < list.Exprs);
Expr orig = list.Ids[colId].Expr; // The iCol-th column of the result set
Debug.Assert(orig != null);
Debug.Assert((orig.Flags & EP.Resolved) != 0);
Context ctx = parse.Ctx; // The database connection
Expr dup = Expr.Dup(ctx, orig, 0); // Copy of pOrig
if (orig.OP != TK.COLUMN && (type.Length == 0 || type[0] != 'G'))
{
IncrAggFunctionDepth(dup, subqueries);
dup = Expr.PExpr_(parse, TK.AS, dup, null, null);
if (dup == null)
{
return;
}
if (list.Ids[colId].Alias == 0)
{
list.Ids[colId].Alias = (ushort)(++parse.Alias.length);
}
dup.TableId = list.Ids[colId].Alias;
}
if (expr.OP == TK.COLLATE)
{
dup = Expr.AddCollateString(parse, dup, expr.u.Token);
}
// Before calling sqlite3ExprDelete(), set the EP_Static flag. This prevents ExprDelete() from deleting the Expr structure itself,
// allowing it to be repopulated by the memcpy() on the following line.
E.ExprSetProperty(expr, EP.Static);
Expr.Delete(ctx, ref expr);
expr.memcpy(dup);
if (!E.ExprHasProperty(expr, EP.IntValue) && expr.u.Token != null)
{
Debug.Assert((dup.Flags & (EP.Reduced | EP.TokenOnly)) == 0);
dup.u.Token = expr.u.Token;
dup.Flags2 |= EP2.MallocedToken;
}
C._tagfree(ctx, ref dup);
}
static void FKScanChildren(Parse parse, SrcList src, Table table, Index index, FKey fkey, int[] cols, int regDataId, int incr)
{
Context ctx = parse.Ctx; // Database handle
Vdbe v = parse.GetVdbe();
Expr where_ = null; // WHERE clause to scan with
Debug.Assert(index == null || index.Table == table);
int fkIfZero = 0; // Address of OP_FkIfZero
if (incr < 0)
{
fkIfZero = v.AddOp2(OP.FkIfZero, fkey.IsDeferred, 0);
}
// Create an Expr object representing an SQL expression like:
//
// <parent-key1> = <child-key1> AND <parent-key2> = <child-key2> ...
//
// The collation sequence used for the comparison should be that of the parent key columns. The affinity of the parent key column should
// be applied to each child key value before the comparison takes place.
for (int i = 0; i < fkey.Cols.length; i++)
{
int col; // Index of column in child table
Expr left = Expr.Expr(ctx, TK.REGISTER, null); // Value from parent table row
if (left != null)
{
// Set the collation sequence and affinity of the LHS of each TK_EQ expression to the parent key column defaults.
if (index != null)
{
col = index.Columns[i];
Column colObj = table.Cols[col];
if (table.PKey == col)
{
col = -1;
}
left.TableId = regDataId + col + 1;
left.Aff = colObj.Affinity;
string collName = colObj.Coll;
if (collName == null)
{
collName = ctx.DefaultColl.Name;
}
left = Expr.AddCollateString(parse, left, collName);
}
else
{
left.TableId = regDataId;
left.Aff = AFF.INTEGER;
}
}
col = (cols != null ? cols[i] : fkey.Cols[0].From);
Debug.Assert(col >= 0);
string colName = fkey.From.Cols[col].Name; // Name of column in child table
Expr right = Expr.Expr(ctx, TK.ID, colName); // Column ref to child table
Expr eq = Expr.PExpr(parse, TK.EQ, left, right, 0); // Expression (pLeft = pRight)
where_ = Expr.And(ctx, where_, eq);
}
// If the child table is the same as the parent table, and this scan is taking place as part of a DELETE operation (operation D.2), omit the
// row being deleted from the scan by adding ($rowid != rowid) to the WHERE clause, where $rowid is the rowid of the row being deleted.
if (table == fkey.From && incr > 0)
{
Expr left = Expr.Expr(ctx, TK.REGISTER, null); // Value from parent table row
Expr right = Expr.Expr(ctx, TK.COLUMN, null); // Column ref to child table
if (left != null && right != null)
{
left.TableId = regDataId;
left.Aff = AFF.INTEGER;
right.TableId = src.Ids[0].Cursor;
right.ColumnId = -1;
}
Expr eq = Expr.PExpr(parse, TK.NE, left, right, 0); // Expression (pLeft = pRight)
where_ = Expr.And(ctx, where_, eq);
}
// Resolve the references in the WHERE clause.
NameContext nameContext; // Context used to resolve WHERE clause
nameContext = new NameContext(); // memset( &sNameContext, 0, sizeof( NameContext ) );
nameContext.SrcList = src;
nameContext.Parse = parse;
ResolveExprNames(nameContext, ref where_);
// Create VDBE to loop through the entries in src that match the WHERE clause. If the constraint is not deferred, throw an exception for
// each row found. Otherwise, for deferred constraints, increment the deferred constraint counter by incr for each row selected.
ExprList dummy = null;
WhereInfo whereInfo = Where.Begin(parse, src, where_, ref dummy, 0); // Context used by sqlite3WhereXXX()
if (incr > 0 && !fkey.IsDeferred)
{
E.Parse_Toplevel(parse).MayAbort = true;
}
v.AddOp2(OP.FkCounter, fkey.IsDeferred, incr);
if (whereInfo != null)
{
Where.End(whereInfo);
}
// Clean up the WHERE clause constructed above.
Expr.Delete(ctx, ref where_);
if (fkIfZero != 0)
{
v.JumpHere(fkIfZero);
}
}