ORA-01219: database not open: queries allowed on fixed tables/views only
First of all check the status of the instance you work with (this may need to connect under administrator account):
select status from v$instance;Probably you will get
STATUS------------MOUNTEDUnder sys account try to complete
ALTER DATABASE OPEN;and check that it's completed successfuly.If not - please share the result of output and alert log in your question.
just in case if someone comes to here for this question
RECOVER DATABASE;and then ALTER DATABASE OPEN;
fixed my issue.
SQL>
ALTER DATABASE OPEN;ALTER DATABASE OPEN *ERROR at line 1:ORA-01113: file 1 needs media recoveryORA-01110: data file 1: 'C:\APP\ADMINISTRATOR\ORADATA\WIND\SYSTEM01.DBF'