Author Question: Explain sequences and their relationship to surrogate keys. What will be an ideal ... (Read 33 times)

Brittanyd9008 · **on:** Jul 7, 2018

Explain sequences and their relationship to surrogate keys.

What will be an ideal response?

Question 2

For use with this book, it is recommended that MySQL be configured as a developer machine.

Indicate whether the statement is true or false

Jody Vaughn · **Reply #1 on:** Jul 7, 2018

Answer to Question 1

A sequence is an Oracle Database object that generates a sequential series of unique numbers. It allows the developer to specify the sequence's starting value and increment. Sequences are useful for specifying surrogate keys. The sequence methods CurrVal and NextVal may be used to access the row with the current sequence number and the next sequence number respectively. Using sequences, however, does not guarantee valid surrogate key values. For example, there is nothing that forces the surrogate key field to use the numbers generated by the sequence; therefore, a record may be inserted that does not follow the sequence. This means code must be written to control surrogate key values when sequences are used. Nonetheless, sequences are the best way to work with surrogate keys in Oracle Database.

Answer to Question 2

FALSE