Oracle External Table

Suppose we have a text file named “emp.data”. This text files contains employees data in following format,

1, Michle , clerk
2, king , manager
3, joe , clerk

What if we want to use this data in SQL query? Remember we do not want to import this data in oracle database but we want to reference this data from its physical location. To achieve this oracle database has provided a feature called External Tables. Using this feature, we can register “emp.dat” file in oracle database as external table. Continue reading “Oracle External Table”

Archivelog mode concepts | Oracle Hot backup and cold backup

We take complete physical backup of database by copying physical database files including datafiles, control files, password file and parameter file. Backup can be online backup or offline backup. In online backup, our database is in open stage and datafiles have different SCN. Continue reading “Archivelog mode concepts | Oracle Hot backup and cold backup”