1 – AREAS
Specifies that the target of the data reorganization is storage
areas. All rows are checked to see if they are in the correct
storage area and if some are not, they are moved. This is the
default.
2 – COMMENT_IS
Adds or alters a comment about the storage map. SQL displays
the text of the comment when it executes a SHOW STORAGE MAPS
statement. Enclose the comment in single quotation marks (') and
separate multiple lines in a comment with a slash mark (/).
3 – COMPILE
Creates a SQL mapping routine that matches the WITH LIMIT OF
clause for the storage map. The routine is automatically created
in the system module RDB$STORAGE_MAPS (use SHOW SYSTEM MODULES to
view). The storage map name is used to name the mapping routine
(use SHOW SYSTEM FUNCTIONS to view).
NOTE
If a routine already exists with the same name as the
storage map, then the mapping routine will not be created.
If the storage map includes a STORE COLUMNS clause, that is,
a vertically partitioned map, then several routines will be
created and uniquely named by adding the vertical partition
number as a suffix.
The mapping routine returns the following values:
o Zero (0) if the storage map is defined as RANDOMLY ACROSS.
This routine is just a descriptive place holder.
o Positive value representing the storage map number (the
same value as stored in RDB$ORDINAL_POSITION column of the
RDB$STORAGE_MAP_AREAS table). These values can be used with
the PARTITION clause of the SET TRANSACTION...RESERVING clause
to reserve a specific partition prior to inserting the row.
o A value of -1 if the storage map has no OTHERWISE clause. This
indicates that the row cannot be inserted because it does not
match any of the WITH LIMIT OF clauses.
4 – COMPRESSION
Syntax options:
ENABLE COMPRESSION | DISABLE COMPRESSION
Changes whether the rows for the table are compressed or
uncompressed when stored. Enabling compression conserves disk
space, but it incurs additional CPU overhead for inserting and
retrieving compressed rows.
Changing the COMPRESSION clause causes the database system
to read all the rows in the table and write them back to the
table in the changed format. If compression is enabled and you
subsequently disable it, records may become fragmented because
the space allowed for the record is no longer large enough.
5 – FILL
Syntax options:
FILL RANDOMLY | FILL SEQUENTIALLY
Specifies whether to fill the area set randomly or sequentially.
Specifying FILL RANDOMLY or FILL SEQUENTIALLY requires a FOR
clause. When a storage area is filled, it is removed from the
list of available areas. Oracle Rdb does not attempt to store
any more lists in that area during the current database attach.
Instead, Oracle Rdb starts filling the next specified area.
When a set of areas is filled sequentially, Oracle Rdb stores
lists in the first specified area until that area is filled.
If the set of areas is filled randomly, lists are stored across
multiple areas. This is the default. Random filling benefits from
the I/O distribution across the storage areas.
The keywords FILL RANDOMLY and FILL SEQUENTIALLY can only be
applied to areas contained within an area list.
6 – FOR (table name)
Specifies the table or tables to which this storage map applies.
The named table must already be defined. If you want to store
lists of more than one table in the storage area, separate the
names of the tables with commas. For each area, you can specify
one FOR clause and a , do not use this statement unless all areas
specified list of table names.
7 – FOR (table name.col name)
Specifies the name of the table and column containing the list
to which this storage map applies. Separate the table name and
the column name with a period (.). The named table and column
must already be defined. If you want to store multiple lists
in the storage area, separate the table name and column name
combinations with commas. For each area, you can specify one FOR
clause and a list of column names.
8 – LOGGING
The LOGGING clause specifies that the ALTER STORAGE MAP statement
should be logged in the recovery-unit journal file (.ruj) and
after-image journal file (.aij). The LOGGING clause is the
default.
9 – NOLOGGING
The NOLOGGING clause specifies that the ALTER STORAGE MAP
statement should not be logged in the recovery-unit journal file
(.ruj) and after-image journal file (.aij).
10 – NO_PLACEMENT_VIA_INDEX
Negates the PLACEMENT VIA INDEX clause so that subsequent
records stored are not stored by means of the index named in
the PLACEMENT VIA INDEX clause. If you specify the ALTER STORAGE
MAP statement without the PLACEMENT VIA INDEX argument or the
NO PLACEMENT VIA INDEX argument, the statement executes as if
the clause specified on the CREATE STORAGE MAP statement or last
ALTER STORAGE MAP statement was used.
11 – NO_REORGANIZE
Disables the reorganize action for PARTITIONING IS NOT UPDATABLE.
12 – PAGES
Specifies that the target of the data reorganization is database
pages. All rows are checked to determine whether they are in the
correct storage area and if some are not, they are moved. Then,
all rows are checked if any should be moved within each storage
area, and these rows are moved if there is space on or closer to
the new target page.
13 – PARTITION name
Names the partition. The name can be a delimited identifier
if the dialect is set to SQL99. Partition names must be unique
within the storage map. If you do not specify this clause, Oracle
Rdb generates a default name for the partition.
14 – PARTITIONING_IS_UPDATABLE
Specifies that the partitioning key can be modified. The
partitioning key is the column or list of columns specified in
the STORE USING clause.
See the Oracle Rdb Guide to Database Design and Definition for
more information regarding partitioning.
15 – PLACEMENT_VIA_INDEX
See the CREATE STORAGE_MAP statement for details of the PLACEMENT
VIA INDEX argument.
16 – RENAME_PARTITION
Syntax options:
RENAME PARTITION partition-name TO new-partition-name
Specifies a new name for an existing storage map partition.
17 – REORGANIZE
Causes new rows and rows previously stored in specified tables
to be moved according to the partitions specified in the STORE
clause of the ALTER STORAGE MAP statement. The REORGANIZE clause
works for one or more areas in the storage maps.
For details of how rows are moved or not moved among storage
areas depending on whether or not the REORGANIZE argument is
specified, see the Oracle Rdb Guide to Database Design and
Definition.
18 – STORAGE MAP map name
Specifies the name of the storage map you want to alter.
19 – store-clause
A new storage map definition that replaces the existing storage
map. The store-clause allows you to specify which storage area
files will be used to store rows from the table. Note that:
o All rows of a table can be associated with a single storage
area.
o Rows of a table can be distributed among several storage
areas.
o Rows of a table can be systematically distributed
(horizontally partitioned) among several storage areas by
specifying upper limits on the values for a column in a
particular storage area.
The store-clause specifies only how you want to associate rows
with areas and not the manner in which rows are assigned to pages
within an area.
See the CREATE STORAGE_MAP statement for a description of the
syntax for the store-clause. However, the effect of the clause
in the ALTER STORAGE MAP statement depends on how you change the
existing storage map.
20 – STORE LISTS IN area name
Directs the database system to store the lists from tables in a
specified storage area. You can store lists from different tables
in the same area. You can create only one storage map for lists
within each database.
You must specify the default storage area for lists. This should
be the LIST STORAGE AREA specified on CREATE DATABASE, or if
none, the DEFAULT STORAGE AREA, or if none, then it will be
RDB$SYSTEM.
For more information, see the CREATE STORAGE_MAP statement.
21 – threshold-clause
Specifies SPAM thresholds for logical areas with uniform format
pages.
When you specify the THRESHOLD clause without enclosing it in
parentheses, you are specifying the default threshold values
for all areas specified in the ALTER STORAGE MAP statement.
You cannot alter the thresholds for any storage areas which are
part of the storage map. Only specify this clause for storage
areas being added to the storage area by the ALTER STORAGE MAP
statement.
To specify threshold values for a particular storage area,
specify the clause as part of the STORE clause and enclose the
THRESHOLD clause in parentheses. You can only specify threshold
values for new areas, not existing ones.
For examples of specifying the THRESHOLD clause, see the Oracle
Rdb Guide to Database Design and Definition. See the CREATE
STORAGE_MAP statement for a description of the THRESHOLDS clause.