290 ◾ Cloud Database Development and Management
e above SQL statement is described below:
◾ boundary_value: is value is used to redefine partitions. e type of the value should be
consistent with the data type of the federation key.
◾ SPLIT AT: At the boundary value, split a federation member to two new federation mem-
bers. e atomic units with the federation key less than the boundary_value are moved to
one of the new federation members and the rest of the atomic units are moved to the other
new federation member.
◾ DROP AT: Drop the federation members identified by the boundary_value. When LOW
is used, drop the federation members below the boundary value and extend the range of the
federation members above the boundary_value to include ...