Question { 4173 }

what is bit map and character mode

Answer

if you want to display images,font style,etc you should use
bit map mode.
chatacter mode allows only characters

Question { Oracle, 8223 }

what is place holder column

Answer

Place holder column is a column for which you set the
datatype and value in pl/sql that you difine
you can set the value of a placeholder column in the
following places
1. the before report trigger, if the placeholder is a
report_level column.
2. A report level formula column,if the placeholder is a
report_level column.
3. A formula in the placeholders group or a group below
it(the value is set once for each record of the group)

Question { HCL, 22052 }

diff between DELETE and TRUNCATE?.

Answer

Delete command is a dml command
truncate command is a ddl command

Delete command has a where clause.
truncate hasn't where clause.

Delete doesn't release memory space(means we can rollback
the deleted rows)
truncate releases memory space(means we can't rollback)

By using synonym we can delete a rows(Delete command).
By using synonym we can't delete a rows(Truncate command).