SQL plus and plsql cannot be used to connect to the Oracle Database System for troubleshooting and cause analysis.

SQL plus and plsql cannot be used to connect to the Oracle Database System for troubleshooting and cause analysis.

Database connection problems:

Sqlplus and plsql cannot connect to Oracle 11g Database system problems or sqlplus can be connected while plsql cannot be connected.

Problem 1: sqlplus cannot connect to the Oracle Database System Solution:

1. Modify the path value in the environment variable: Move the bin directory of your database to the beginning.

2. The modification is complete. Run cmd again.

Cause: When the database is started, the oracle path in the first system environment variable is selected for running. If the system is not changed, it will be considered as logging on to the Database System of mongoel 10 Gb without the user information we logged on.

Problem 2: sqlplus can be connected, while plsql cannot be connected to the Oracle database system. Solution:

Go to the plsql login not page, select [settings]-[Preferences], select "Oracle Home Directory Name" as "11 GB", then restart Plsql, and then log on again.

Cause: If the Oracle Home Directory is not configured, plsql defaults to the previous Oracle 10g Database Home Directory and can only log on to the Oracle 10g Database System.