oceanbase中存储过程的实现（一）语法解析部分
技术背景 淘宝的开源数据库oceanbase 是一个支持海量数据的高性能分布式数据库系统，实现了数千亿条记录、数百TB数据上的跨行跨表事务，由淘宝核心系统研发部开发的。 但是现在oceanbase0.4版本是不支持很多功能的，其中包括存储过程。 开发方案 淘宝数据使
技术背景
淘宝的开源数据库oceanbase 是一个支持海量数据的高性能分布式数据库系统，实现了数千亿条记录、数百TB数据上的跨行跨表事务，由淘宝核心系统研发部开发的。
但是现在oceanbase0.4版本是不支持很多功能的，其中包括存储过程。
开发方案
淘宝数据使用的是flex&bison来进行sql语句的解析的，因此我们在做存储过程的语法也应该用它的方案实现。
我们经过语法解析过后需要用一种数据结构来存储语法树，一种方法是使用OB里面的节点设计，另一种是使用Postgrepsql的节点设计来存储它
OceanBase的语法树的节点设计
OceanBase的语法树节点结构体也只有一个,该结构体包括一个枚举类型变量type_,和PostgreSQL一样，代表该结构体对应的类型。还有两组属性，对应终止符节点,只能使用vakue_和str_value_两个字段，分别对应64位整形值和字符串值；非终止符节点使用最后两个字段,num_child_表示子节点的个数,children_指向子节点数组的首地址。
存储过程语法树
上面部分是通过语法解析部分得到的一颗语法树。
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