import (
	"database/sql"
	"database/sql/driver"
	"go/ast"
	"reflect"
)

// Expression expression interface
type Expression interface {
	Build(builder Builder)
}

// NegationExpressionBuilder negation expression builder
type NegationExpressionBuilder interface {
	NegationBuild(builder Builder)
}

// Expr raw expression
type Expr struct {
	SQL                string
	Vars               []interface{}

  TF_Operation* neg = Neg(feed, func_graph_, s_, "neg");
  Define(-1, {}, {feed}, {neg}, {"negation"});

  // Use, run, and verify
  TF_Operation* func_feed = Placeholder(host_graph_, s_);
  TF_Operation* func_op = Use({func_feed});
  Run({{func_feed, Int32Tensor(3)}}, func_op, -3);
  VerifyFDef({"neg"}, {{"negation_0", DT_INT32}}, {{"negation", DT_INT32}},

</pre>

<p>
For floating-point arguments negative zero, NaN, and infinity the following rules apply:
</p>

<pre>
   x        y    min(x, y)    max(x, y)

  -0.0    0.0         -0.0          0.0    // negative zero is smaller than (non-negative) zero
  -Inf      y         -Inf            y    // negative infinity is smaller than any other number

	}

	checkStructRelation(t, &User{}, Relation{
		Name: "Profiles", Type: schema.Many2Many, Schema: "User", FieldSchema: "Profile",
		JoinTable: JoinTable{Name: "user_profiles", Table: "user_profiles"},
		References: []Reference{
			{"Refer", "User", "UserReferID", "user_profiles", "", true},
			{"UserRefer", "Profile", "ProfileRefer", "user_profiles", "", false},
		},
	}, Relation{

			relation.FieldSchema.Relationships.Relations["_"+relation.Schema.Name+"_"+relation.Name] = relation
			relation.FieldSchema.Relationships.Mux.Unlock()
		}

		switch field.IndirectFieldType.Kind() {
		case reflect.Struct:
			relation.Type = HasOne
		case reflect.Slice:
			relation.Type = HasMany
		}
	}

	if schema.err == nil {
		schema.setRelation(relation)
		switch relation.Type {
		case HasOne:

        public abstract String symbol();

        public static ScaleUnit getScaleUnit(long size) {
            if (size < 0L) {
                throw new IllegalArgumentException("file size cannot be negative: " + size);
            }

            if (size >= GIGABYTE.bytes()) {
                return GIGABYTE;
            } else if (size >= MEGABYTE.bytes()) {
                return MEGABYTE;

		preloadFields := strings.Split(name, ".")
		value := strings.TrimPrefix(strings.TrimPrefix(name, preloadFields[0]), ".")
		if preloadFields[0] == clause.Associations {
			for _, relation := range s.Relationships.Relations {
				if relation.Schema == s {
					setPreloadMap(relation.Name, value, args)
				}
			}

			for embedded, embeddedRelations := range s.Relationships.EmbeddedRelations {
				for _, value := range embeddedValues(embeddedRelations) {

func checkSchemaRelation(t *testing.T, s *schema.Schema, relation Relation) {
	t.Run("CheckRelation/"+relation.Name, func(t *testing.T) {
		if r, ok := s.Relationships.Relations[relation.Name]; ok {
			if r.Name != relation.Name {
				t.Errorf("schema %v relation name expects %v, but got %v", s, r.Name, relation.Name)
			}

			if r.Type != relation.Type {
				t.Errorf("schema %v relation name expects %v, but got %v", s, r.Type, relation.Type)

							for _, relname := range nestedJoinNames {
								// incomplete match, only treated as raw sql
								if relation, ok = currentRelations[relname]; ok {
									guessNestedRelations = append(guessNestedRelations, relation)
									currentRelations = relation.FieldSchema.Relationships.Relations
								} else {
									isNestedJoin = false
									break
								}
							}

        public abstract String symbol();

        public static ScaleUnit getScaleUnit(long size) {
            if (size < 0L) {
                throw new IllegalArgumentException("file size cannot be negative: " + size);
            }

            if (size >= GIGABYTE.bytes()) {
                return GIGABYTE;
            } else if (size >= MEGABYTE.bytes()) {
                return MEGABYTE;