Lost connection to MySQL server…
[ERROR] InnoDB: Expected to open 3 undo tablespaces but was able to find only 0 undo tablespaces. Set the innodb_undo_tablespaces parameter to the correct value and retry. Suggested value is 0
ERROR 1418 (HY000): This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable)
Error Code: 1175. You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column.
Error 1390 (HY000): Prepared statement contains too many placeholders
设计模式 -- 单例模式（Singleton Pattern）
设计模式的六大原则
在SQL Server数据库中，可以通过修改字段的长度来调整数据库中存储的数据的大小。字段长度是指字段可以存储的字符或字节的数量。修改字段长度的操作可以用于多种情况，比如增加或减少字段的容量、优化性能、遵循数据库设计规范等。
接口数据类型与表单提交数据类型，在大多数情况下，大部分属性的类型是相同的，但很少能做到完全统一。
Vue生命周期中mounted和created的区别
