Database Reference
In-Depth Information
Object improvements include VARRAY resizing and splitting of
nested table type columns into different tablespaces (see Chapter 16).
A new row timestamp pseudocolumn called ORA_ROWSCN con-
tains a commit point timestamp or system change number (SCN).
For updates only, the SCN for a row must be retrieved to ensure that
no row change occurred between a row SELECT and subsequent
UPDATE.
The following new datatypes have been added (see Chapter 16):
BINARY_FLOAT and BINARY_DOUBLE allow 32-bit single
precision and 64-bit double precision floating-point numbers.
SDO_GEORASTER and SI_STILLIMAGE store raster and dig-
ital images, respectively (including object characteristics), for
object-relational multimedia storage.
A multitude of DDL commands have been altered and enhanced.
Most DDL command changes are relevant to database administra-
tion and not Oracle SQL.
Several SELECT statement and DML command syntax changes have
been introduced:
MERGE allows insertions, updates, or both. Previously, the
MERGE command always performed both insertions and
updates. Additionally, MERGE can also delete rows from the tar-
get table (see Chapter 15).
SELECT can be executed as a flashback or versions query, retriev-
ing data at a point in time in the past, based on an SCN or times-
tamp (see Chapter 13).
Grouped outer joins allow groupings on data where subset parts
may not exist.
Note:
Grouped outer joins are omitted from this topic because syntax
documentation was not available at the time of writing.
The SPREADSHEET clause extends the SELECT statement,
allowing multiple dimensional array query result output. Calcu-
lations between resulting rows can be performed much like
cross-tabbing or interdimensional data warehouse reporting (see
Chapter 11).
