*, sqlplus connects to local data
sqlplus / as sysdba; If you add @ instance name after /, you can log in to the specified instance service, otherwise enter the default instance
Note: This method defaults to logging in to the system as the sys user, so when using it, remember that the consequences caused by excessive permissions such as data loss
*, conn of sqlplus
conn username/key; switch to another user
*, sqlplus login to remote database
sqlplus username/key@IP:Port/sid (instance name)
Note: Remember that there can be no semicolon, semicolon, no semicolon after this statement
*, sqlplus local or remote login database, the main premise is that when there are multiple instances, when there are multiple instances, multiple instances
sqlplus username/key@IP:Port/sid (instance name)
Note: Remember that this statement must have IP
*, see remote import and export for details
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