* @return the corresponding map from column keys to values
   */
  Map<C, V> row(@ParametricNullness R rowKey);

  /**
   * Returns a view of all mappings that have the given column key. For each row key / column key /
   * value mapping in the table with that column key, the returned map associates the row key with
   * the value. If no mappings in the table have the provided column key, an empty map is returned.
   *

				Columns: []clause.OrderByColumn{{Column: clause.PrimaryColumn, Desc: true}},
			}},
			"SELECT * FROM `users` ORDER BY `users`.`id` DESC", nil,
		},
		{
			[]clause.Interface{
				clause.Select{}, clause.From{}, clause.OrderBy{
					Columns: []clause.OrderByColumn{{Column: clause.PrimaryColumn, Desc: true}},
				}, clause.OrderBy{
					Columns: []clause.OrderByColumn{{Column: clause.Column{Name: "name"}}},
				},
			},

		},
		{
			[]clause.Interface{clause.Select{
				Columns: []clause.Column{clause.PrimaryColumn},
			}, clause.From{}},
			"SELECT `users`.`id` FROM `users`", nil,
		},
		{
			[]clause.Interface{clause.Select{
				Columns: []clause.Column{clause.PrimaryColumn},
			}, clause.Select{
				Columns: []clause.Column{{Name: "name"}},
			}, clause.From{}},
			"SELECT `name` FROM `users`", nil,
		},
		{

								if ref.OwnPrimaryKey {
									exprs[idx] = clause.Eq{
										Column: clause.Column{Table: parentTableName, Name: ref.PrimaryKey.DBName},
										Value:  clause.Column{Table: tableAliasName, Name: ref.ForeignKey.DBName},
									}
								} else {
									if ref.PrimaryValue == "" {
										exprs[idx] = clause.Eq{
											Column: clause.Column{Table: parentTableName, Name: ref.ForeignKey.DBName},

						queryConds = append(queryConds, clause.Eq{
							Column: clause.Column{Table: rel.JoinTable.Table, Name: ref.ForeignKey.DBName},
							Value:  ref.PrimaryValue,
						})
					}
				}

				_, foreignValues := schema.GetIdentityFieldValuesMap(db.Statement.Context, db.Statement.ReflectValue, foreignFields)
				column, values := schema.ToQueryValues(table, relForeignKeys, foreignValues)

			clause.Eq{Column: column, Value: (*string)(nil)},
			clause.Eq{Column: column, Value: (*int)(nil)},
			clause.Eq{Column: column, Value: (*bool)(nil)},
			clause.Eq{Column: column, Value: (interface{})(nil)},
			clause.Eq{Column: column, Value: sql.NullString{String: "", Valid: false}},
		},
		Result: "`column-name` IS NULL",
	}, {
		Expressions: []clause.Expression{

				if _, ok := db.Statement.Clauses["RETURNING"]; !ok {
					fromColumns := make([]clause.Column, 0, len(db.Statement.Schema.FieldsWithDefaultDBValue))
					for _, field := range db.Statement.Schema.FieldsWithDefaultDBValue {
						fromColumns = append(fromColumns, clause.Column{Name: field.DBName})
					}
					db.Statement.AddClause(clause.Returning{Columns: fromColumns})
				}
			}
		}

			}},
			"SELECT * FROM `users` WHERE `users`.`id` = ? OR `name` <> ? AND `age` > ?",
			[]interface{}{"1", "jinzhu", 18},
		},
		{
			[]clause.Interface{clause.Select{}, clause.From{}, clause.Where{

	for idx, key := range keys {
		assignments[idx] = Assignment{Column: Column{Name: key}, Value: values[key]}
	}
	return assignments
}

func AssignmentColumns(values []string) Set {
	assignments := make([]Assignment, len(values))
	for idx, value := range values {
		assignments[idx] = Assignment{Column: Column{Name: value}, Value: Column{Table: "excluded", Name: value}}
	}
	return assignments

			} else if eq, ok := expr.(clause.Eq); ok {
				switch column := eq.Column.(type) {
				case string:
					assigns[column] = eq.Value
				case clause.Column:
					assigns[column.Name] = eq.Value
				}
			}
		}

		return tx.Model(dest).Updates(assigns)
	}

	return tx
}