SQL/MP Reference Manual

HP NonStop SQL/MP Reference Manual—523352-013
A-40
Considerations—ALTER TABLE
For example, an existing row receives the value 0001-01-01:12:00:00.000000
in the new column if the data type is DATETIME YEAR TO FRACTION,
receives the value 0001-01-01 in the new column if the data type is DATE,
receives the value 12:00:00 in the new column if the data type is TIME, and so
forth.
Any row added after the ADD COLUMN operation finishes that does not
contain a value for the column receives a default value based on the current
timestamp at the time the row is added.

The sum of the lengths of all columns for a table cannot exceed the maximum
row length for the table (the block size minus the header size). For information
about additional restrictions on the number of columns allowed, see Limits
on
page L-6.

You cannot add a column to a table with relative file organization unless the
row length of the table is large enough to accommodate the added column.
You cannot add a column to a table with entry-sequenced file organization
under any circumstances.

The new column is not actually added to a row until the row is updated. If you
select a row that does not yet have the new column, SQL returns the default
value for the column.

MOVE can perform a simple move operation for a table of any file organization,
and can perform a one-way or two-way split (to new partitions), merge (into an
existing partition), or one-way move (to an existing partition) for a table with a
key-sequenced file organization.

A simple move moves a partition to another volume:
MOVE TO dest-part [WITH SHARED ACCESS]
name specifies the name of the partition to be moved. You can specify a simple
move with or without the WITH SHARED ACCESS option.

A merge operation moves the partition into another existing partition, deleting
the original partition:
MOVE TO dest-part WITH SHARED ACCESS
In a merge request, name specifies the actual partition being moved. The
WITH SHARED ACCESS option is required.

A one-way split moves the first or last part of a partition to a new partition,
leaving the remaining part in the existing partition:
MOVE FROM KEY val TO dest-part [WITH SHARED ACCESS]
MOVE UP TO KEY val TO dest-part WITH SHARED ACCESS
In a one-way split, name specifies the table for the operation. The partition that
is split is the one whose data range includes the key val, even if the specified
partition does not actually contain a row with that key.