Oracle 9i 数据库异常关闭后的启动
正在看的ORACLE教程是:Oracle 9i 数据库异常关闭后的启动。 Oracle 数据库启动Oracle shutdown的时候突然断电,导致使用sql/plus启动时无法连接到数据库,具体描述为:
connection can not permitted, shut in progress.
到dos 提示符 键入:
c:\> sqlplus /nolog
显示:
sql/plus: Realease9.0.2……..all rights reserved
sql> connect /as sysdba
显示已连接至空闲例程
sql>startup 显示shutdown in progress.
到sqlplus 里面连接:
sys/manager@orcl92 显示信息连接成功。
Sql: select * from tab;
显示norows selected;
表明:没有启动数据库。 后来查阅相关资料:得出解决方法:
到dos 提示符 键入:
c:\> sqlplus /nolog
显示 sql/plus: Realease9.0.2……..all rights reserved
sql> connect /as sysdba
显示已连接至空闲例程
sql> startup force
显示:已启动。数据库已正常启动。
也可以先将 windows services中将oraclehome92 service 停止,再启动oracle enterprise manager console,选择独立启动,选择数据库,点击orcl(全局数据库名),弹出对话框,输入用户名system密码password,连接身份:sysdba,选择例程,配置,在一般信息标签下将例程状态先改为关闭,在打开。如果提示oraclehome92 service 停止,则将这个服务启动起来,再启动数据库,也可解决问题。
附:startup force 强制启动一个没有关闭或没能正常启动的数据库;过程:先关闭实例,再启动。
Startup restrict 以限制模式启动数据库,从而限制访问数据库,只有具有 restricted session 权限的用户能与数据库连接
alter system [enable/disable] restricted session 在数据库打开后,该语句启动或关闭访问限制功能。如果相对主结构做更改或想得到导出一致性,应将数据库设置为限制模式。 只有具有alter system权限,才可以用alter system [enable/disable] restricted session 命令改变数据库的可用性。
当一个实例以nomount状态启动时,只能访问sga读取数据的视图。关于 v$thread,v$controlftle等信息从sga 读取数据的词典视图。当数据库被装配时,关于 v$thread,v$controlftle等信息从控制文件中被读出。
分析,当数据库异常关闭时,shutdown在程序里没有退出,因此启动实例时检测到shutdown,则系统报错。因此需要先关闭数据库,再启动数据库。

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MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA


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