Function HasNeighborsWith

dialect/sql/sqlgraph/graph.go:281–353

HasNeighborsWith applies on the given Selector a neighbors check. The given predicate applies its filtering on the selector.

(q *sql.Selector, s *Step, pred func(*sql.Selector))

// HasNeighborsWith applies on the given Selector a neighbors check.
// The given predicate applies its filtering on the selector.
func HasNeighborsWith(q *sql.Selector, s *Step, pred func(*sql.Selector)) {
	builder := sql.Dialect(q.Dialect())
	switch {
	case s.ThroughEdgeTable():
		pk1, pk2 := s.Edge.Columns[1], s.Edge.Columns[0]
		if s.Edge.Inverse {
			pk1, pk2 = pk2, pk1
		}
		to := builder.Table(s.To.Table).Schema(s.To.Schema)
		edge := builder.Table(s.Edge.Table).Schema(s.Edge.Schema)
		join := builder.Select(edge.C(pk2)).
			From(edge).
			Join(to).
			On(edge.C(pk1), to.C(s.To.Column))
		matches := builder.Select().From(to)
		matches.WithContext(q.Context())
		pred(matches)
		join.FromSelect(matches)
		q.Where(sql.In(q.C(s.From.Column), join))
	case s.FromEdgeOwner():
		to := builder.Table(s.To.Table).Schema(s.To.Schema)
		// Avoid ambiguity in case both source
		// and edge tables are the same.
		if s.To.Table == q.TableName() {
			to.As(fmt.Sprintf("%s_edge", s.To.Table))
			// Choose the alias name until we do not
			// have a collision. Limit to 5 iterations.
			for i := 1; i <= 5; i++ {
				if to.C("c") != q.C("c") {
					break
				}
				to.As(fmt.Sprintf("%s_edge_%d", s.To.Table, i))
			}
		}
		matches := builder.Select(to.C(s.To.Column)).
			From(to)
		matches.WithContext(q.Context())
		matches.Where(
			sql.ColumnsEQ(
				q.C(s.Edge.Columns[0]),
				to.C(s.To.Column),
			),
		)
		pred(matches)
		q.Where(sql.Exists(matches))
	case s.ToEdgeOwner():
		to := builder.Table(s.Edge.Table).Schema(s.Edge.Schema)
		// Avoid ambiguity in case both source
		// and edge tables are the same.
		if s.Edge.Table == q.TableName() {
			to.As(fmt.Sprintf("%s_edge", s.Edge.Table))
			// Choose the alias name until we do not
			// have a collision. Limit to 5 iterations.
			for i := 1; i <= 5; i++ {
				if to.C("c") != q.C("c") {
					break
				}
				to.As(fmt.Sprintf("%s_edge_%d", s.Edge.Table, i))