Learn about the logical columns that exists in oracle database with example queries.

Pseudo columns are nothing but logical columns which behaves like a physical columns in database.

Means Pseudo columns behaves like a table columns but is not actually stored in the table.

You can select from pseudo-columns, but you cannot insert, update, or delete their values.
A pseudo-column is also similar to a function without arguments.
The examples of Pseudo columns are –

  • rowid
  • currval and nextval
  • versions_xid
  • versions_operation
  • versions_startscn
  • versions_endscn
  • sysdate
  • systimestamp
  • rownum
  • ora_rowscn
  • object_value
  • level
  • user

Now our main focus is on rowid, row num, currval, and nextval, level pseudo columns.

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