Assume that, in addition to the operations read(x) and write(x), a database has the operation copy(x,y), which (atomically) copies the value stored in record x into record y. Design a conflict table for these operations for use in an immediate-update pessimistic concurrency control.

What will be an ideal response?


The conflict table is for operations on a single item. Therefore we must distinguish
the cases where the copy is from the item described by the table and when the copy
is to that item. Copy-from is like a read, and copy-to is like a write.

Computer Science & Information Technology

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