摘要： 第一节课：启动数据库并且使用特定用户连接:su - oracle;启动sqlplus并且使用sys连接：conn / as sysdba;启动数据库：startup;解锁用户：alter user hr identified by hr;alter user hr account unlock;使用hr连接：conn hr/hr;select * from tab;desc employees;select * from departments;开发工具：plsql developer;toad特殊字符：SELECT department_name || q'[ Department& 阅读全文