code: func (i Ident) Full(ctx context.Context) (full Ident) {
  	full.Name = i.Name
  	if i.Schema.O != "" {
  		full.Schema = i.Schema
  	} else {
  		full.Schema = model.NewCIStr(ctx.GetSessionVars().CurrentDB)
  	}
  	return
  }
docs: // Full returns an Ident which set schema to the current schema if it is empty.