A table contains a list of all seats available at a football stadium. A seat consists of a section
number, a seat number, and whether or not the seat has been assigned. A ticket agent working at
the box office generates a list of all unassigned seats. When the agent refreshes the list, it should
only change if another agent assigns one or more unassigned seats. Which of the following is the
best isolation level to use for this application?
A.
Repeatable Read
B.
Read Stability
C.
Cursor Stability
D.
Uncommitted Read
Cursor stability
Like levels RR and RS, level Cursor Stability (CS) ensures that any row that was changed (or a row that is currently locked with an UPDATE row lock) by another activation group using a different commitment definition cannot be read until it is committed. Unlike RR and RS, level CS only ensures that the current row of every updatable cursor is not changed by other activation groups using different commitment definitions. Thus, the rows that were read during a unit of work can be changed by other activation groups that use a different commitment definition. In addition to any exclusive locks, an activation group running at level CS may acquire a share lock for the current row of every cursor.
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