Database Reference
In-Depth Information
Note:
The SPREADSHEET clause has been renamed to the
MODEL clause.
Oracle Database 10
g
has recycle bin technology (see Chapter 18):
Recovering a table from the recycle bin requires use of the
FLASHBACK TABLE command.
The PURGE command is used to permanently destroy objects
dropped into the recycle bin. Space is not released for dropped
objects until they are purged.
New built-in functions are as follows:
COLLECT creates a nested table from the row set result of a sin-
gle column in a table (see Chapter 16).
Nested tables have new collection functions (see Chapter 16):
CARDINALITY returns the number of elements in a collec-
tion for each row.
POWERMULTISET returns all set elements in a collection.
POWERMULTISET_BY_CARDINALITY combines the
previous two functions by returning all set elements with a
specified number of entries, for each collection in each row.
One could find every row in a table where that collection has
a specified number of entries.
SET converts a nested table (collection) for each row to a set.
A set contains unique values only such that duplicates are
removed within each collection in each row.
SPREADSHEET clause functions are used to facilitate cross cal-
culations between different rows. Functions include the following
(see Chapter 11):
CURRENTV returns a dimensional value or current value.
PRESENTNNV returns one expression if a value exists, oth-
erwise another.
PRESENTV is as for PRESENTNNV except allowing null
values.
PREVIOUS returns a value at the beginning of each iteration
or loop.
New binary floating-point number functions include the follow-
ing (see Chapter 9):
TO_BINARY_DOUBLE and TO_BINARY_FLOAT allow
for conversions.
