Category Archives: Database

Constraint Exceptions

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When adding or enabling a constraint on a table, it is possible that an error occurs because of an constraint violation.  If for example you are trying to add a unique constraint to a column (or combination of columns) of a table that has duplicates (two ore more rows with the constraint columns having the same values) you will receive… Read more »

Oracle RDBMS Password Hashes

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Within Oracle databases passwords get hashed. When, for example, you create a new account or change the password of an account, the specified clear-text password gets hashed. This hash value is stored in the database with the account. Once hashed it is not possible to get the original clear-text password from the hash value (one-way hash algorithms) again. The case-insentive… Read more »

Unwrapping wrapped PLSQL in 10g, 11g and 12c

There are circumstances where you whish to have a look at the source of an wrapped PL/SQL package, procedure or function. The circumstances I want to have peek at the source is when some PL/SQL code becomes invalidated because an object the code depends on disapears or grants on such objects gets lost. It would/should of course be nice if… Read more »

Unable to monitor ORA-errors in alertlog for databases

There is a problem monitoring Oracle databases in OEM. Alerts for ORA- errors that appear in the alertlog of databases won’t get generated and you will not be able to view the alertlog (time range) for databases of this specific version. The problem is introduced with database version and is caused by the format of the timestamp… Read more »