Use the SQL * Plus query tool to connect to the Oracle database

before connecting to the database server, first, you must enable two Oracle-related services in the control panel-Administrative Tools-service of Windows: oracleorahome92tnslistener (listener service) and oracleservicechstone (instance service ), if the local machine is used as a server and does not accept remote client login, you can simply enable the next instance service.
establish a connection: Start- Program -Oracle-OraHome92-Application development-SQL plus, the Login Dialog Box appears, enter the user name and password, the host string is the previously configured net service name. If it is null, it means to connect to the default database on the local machine.
use start-run to establish a connection:
enter SQL * Plus in the "sqlplus" status, enter "sqlplusw" to enter SQL * Plus in WINDOS state. You can directly enter the user name and password to log in.

for example, "sqlplusw Scott/Tiger". to log on to a remote server, add a host string to the backend, separate the host string with @ and the password. For example, to log on to a remote server, use the net service name we configured above, that is, "sqlplusw Scott/tiger @ testservice ".
the $ symbol is used to execute doscommands in SQL * Plus, such as starting or disabling services:
$ Net start oracleservicechstone (Starting Services)
$ net stop oracleservicechstone