SQL Plus/PL cannot connect to a remote Oracle database

Preface: After installing the Oracle client, SQL Plus and PL/E could not connect to the remote Oracle database, possibly for the following reasons:

Connection not on SQL plus:

1 Possible causes: Before the Oracle database client was installed and not uninstalled cleanly, SQL Plus uses the configuration of the previous Oracle client, causing the connection to not

Workaround: In the system variable, delete the previous Oracle client information, such as path information

In cases where SQL Plus can be connected, no

1 Possible causes: Before the Oracle database client was installed and not uninstalled cleanly, PL/SQL used the configuration of the previous Oracle client, causing the connection to not

WORKAROUND: 1 at the time of landing, click Cancel, automatically enter the interface, follow the operation tools->preferences, enter the configuration interface, find Oracle->connection, on the right side of the configuration interface to find Oracle home, Then you specify Oracle home as the newly installed client

2 possible causes: PL/SQL is installed under strange paths, such as "Program Files" (x86)

Workaround: Uninstall, reload, install under a normal path

SQL Plus/PL cannot connect to a remote Oracle database