func Update(ctx context.Context, tablename string, values map[string]interface{}, condition Condition, transation ...*sql.Tx) error {
	return handler.Update(ctx, tablename, values, condition, transation...)
}
Update record. It only invokes "<DBHandler>.Update"
package db
import (
	"context"
	"database/sql"
)
type DBHandler interface {
	WithContent(query Query, contentType string, option ContentOption) (Query, error)
	BuildQuery(querier Query, count bool) (string, []interface{}, error)
	GetColumns(table string) []string
	Insert(ctx context.Context, tablename string, values map[string]interface{}, transation ...*sql.Tx) (int, error)
	Update(ctx context.Context, tablename string, values map[string]interface{}, condition Condition, transation ...*sql.Tx) error
	Delete(ctx context.Context, tableName string, condition Condition, transation ...*sql.Tx) error
}
var handler DBHandler
func RegisterHandler(dbHandler DBHandler) {
	handler = dbHandler
}
func Insert(ctx context.Context, tablename string, values map[string]interface{}, transation ...*sql.Tx) (int, error) {
	return handler.Insert(ctx, tablename, values, transation...)
}