code: public boolean delete(String tableName, Record record) {
  		String defaultPrimaryKey = config.dialect.getDefaultPrimaryKey();
  		Object t = record.get(defaultPrimaryKey);	// 引入中间变量避免 JDK 8 传参有误
  		return deleteByIds(tableName, defaultPrimaryKey, t);
  	}
docs: <pre>
  Example:
  boolean succeed = Db.use().delete("user", user);
  </pre>
  @see #delete(String, String, Record)