PrimaryKey    *Field
	PrimaryValue  string
	ForeignKey    *Field
	OwnPrimaryKey bool
}

func (schema *Schema) parseRelation(field *Field) *Relationship {
	var (
		err        error
		fieldValue = reflect.New(field.IndirectFieldType).Interface()
		relation   = &Relationship{
			Name:        field.Name,
			Field:       field,
			Schema:      schema,
			foreignKeys: toColumns(field.TagSettings["FOREIGNKEY"]),

	// Columns
	AddColumn(dst interface{}, field string) error
	DropColumn(dst interface{}, field string) error
	AlterColumn(dst interface{}, field string) error
	MigrateColumn(dst interface{}, field *schema.Field, columnType ColumnType) error
	// MigrateColumnUnique migrate column's UNIQUE constraint, it's part of MigrateColumn.
	MigrateColumnUnique(dst interface{}, field *schema.Field, columnType ColumnType) error

	DB.Save(&animal).Update("From", "a nice place") // The name field should be untouched
	DB.First(&animal, animal.Counter)
	if animal.Name != "galeone" {
		t.Errorf("Name fields shouldn't be changed if untouched, but got %v", animal.Name)
	}

	// When changing a field with a default value, the change must occur
	animal.Name = "amazing horse"
	DB.Save(&animal)

					switch column := eq.Column.(type) {
					case string:
						if field := db.Statement.Schema.LookUpField(column); field != nil {
							db.AddError(field.Set(db.Statement.Context, db.Statement.ReflectValue, eq.Value))
						}
					case clause.Column:
						if field := db.Statement.Schema.LookUpField(column.Name); field != nil {
							db.AddError(field.Set(db.Statement.Context, db.Statement.ReflectValue, eq.Value))
						}
					}

	relation, ok := modelSchema.Relationships.Relations[field]
	isRelation := ok && relation.JoinTable != nil
	if !isRelation {
		return fmt.Errorf("failed to find relation: %s", field)
	}

	for _, ref := range relation.References {
		f := joinSchema.LookUpField(ref.ForeignKey.DBName)
		if f == nil {
			return fmt.Errorf("missing field %s for join table", ref.ForeignKey.DBName)
		}

					return
				}
			case schema.Many2Many:
				var (
					queryConds     = make([]clause.Expression, 0, len(rel.References))
					foreignFields  = make([]*schema.Field, 0, len(rel.References))
					relForeignKeys = make([]string, 0, len(rel.References))
					modelValue     = reflect.New(rel.JoinTable.ModelType).Interface()
					table          = rel.JoinTable.Table

				field := stmt.Schema.FieldsByDBName[column.Name]
				if values.Values[0][idx], isZero = field.ValueOf(stmt.Context, stmt.ReflectValue); isZero {
					if field.DefaultValueInterface != nil {
						values.Values[0][idx] = field.DefaultValueInterface
						stmt.AddError(field.Set(stmt.Context, stmt.ReflectValue, field.DefaultValueInterface))
					} else if field.AutoCreateTime > 0 || field.AutoUpdateTime > 0 {

}

// ParseUniqueConstraints parse schema unique constraints
func (schema *Schema) ParseUniqueConstraints() map[string]UniqueConstraint {
	uniques := make(map[string]UniqueConstraint)
	for _, field := range schema.Fields {
		if field.Unique {
			name := schema.namer.UniqueName(schema.Table, field.DBName)
			uniques[name] = UniqueConstraint{Name: name, Field: field}
		}
	}
	return uniques

	expr.SQL = m.DataTypeOf(field)

	if field.NotNull {
		expr.SQL += " NOT NULL"
	}

	if field.HasDefaultValue && (field.DefaultValueInterface != nil || field.DefaultValue != "") {
		if field.DefaultValueInterface != nil {
			defaultStmt := &gorm.Statement{Vars: []interface{}{field.DefaultValueInterface}}
			m.Dialector.BindVarTo(defaultStmt, defaultStmt, field.DefaultValueInterface)

			Name:  "uni_user_uniques_name1",
			Field: &schema.Field{Name: "Name1", Unique: true},
		},
	}
	for k, result := range results {
		v, ok := constraints[k]
		if !ok {
			t.Errorf("Failed to found unique constraint %v from parsed constraints %+v", k, constraints)
		}
		tests.AssertObjEqual(t, result, v, "Name")
		tests.AssertObjEqual(t, result.Field, v.Field, "Name", "Unique", "UniqueIndex")
	}