Oracle Certification Exam Question:
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What is row chaining and row migration?

Answer:

We will migrate a row when an update to that row would cause it to not fit on the block anymore (with all of the other data that exists there currently). A migration means that the entire row will move and we just leave behind the. So, the original block just has the rowid of the new block and the entire row is moved.
Row chaining nstead of just having a forwarding address on one block and the data on another we have data on two or more blocks.

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Explain Which two statements are true regarding single row functions? (Choose two.)
A. They accept only a single argument
B. They can be nested only to two levels
C. Arguments can only be column values or constant
D. They always return a single result row for every row of a queried table
E. They can return a data type value different from the one that is reference		Evaluate the following SQL statements:

DELETE FROM sales;
There are no other uncommitted transactions on the SALES table.
Which statement is true about the DELETE statement?
A. It would not remove the rows if the table has a primary key
B. It removes all the rows as well as the structure of the table
C. It removes all the rows in the table and deleted rows can be rolled back
D. It removes all the rows in the table and deleted rows cannot be rolled back