oracle SQL 解析 步骤，爱好oracle的朋友可以参考下，了解工作流程。
1 The syntax of the SQL statement is verified.
SQL的语法检查
2 The data dictionary is searched to verify table and column definitions.
从数据字典检查表名和字段名
3 The data dictionary is searched to verify security privileges on relevant objects.
从数据字典中检查权限
4 Parse locks are acquired on the relevant objects.
解析相关对象的锁
5 The optimal execution plan is determined.
选在执行计划运行SQL
6 The statement is loaded into the shared SQL area (also known as the library cache) in the shared pool of the system global area (SGA).
执行后SQL语句放在SGA的SQL共享区
