UNIT 3 — MILESTONE
3
16/2
Sophia Introduction to Relational Databases
1
Milestone_3.
16/21 that's 76%
This Milestone has been retaken.
16 questions were answered correctly. 5 questions were
answered incorrectly.
1
In each milestone, you may want or need to use the database
and query tool to answer some of the questions. We suggest
you open the tool in another browser tab while you are working
on this assessment.
https://postgres.sophia.org/
Which type of backup would result in the fastest to RESTORE?
Nightly backup
Incremental backup
Full backup
, Differential backup
RATIONALE
,Full backups are a full copy of the entire data set. Although they
areUNIT
the best3protection,
— MILESTONEthey are time-consuming and quite large to
3 Incremental backups only back up the data that has changed
store.
since the previous backup, even if it's another incremental backup.
16/2
These file sizes are the smallest out of the lot. Differential backups
1
are similar to incremental backups, but they start with a full
backup and include data since the prior full backup. At most, there
are only 2 backups to restore from.
CONCEPT
Backup Methods
Report an issue with this question
2
In each milestone, you may want or need to use the database
and query tool to answer some of the questions. We suggest
you open the tool in another browser tab while you are working
on this assessment.
https://postgres.sophia.org/
Which of the following scenarios reflects the
durability property?
The product quantity starts at 200.
Transaction 1 runs to read the quantity of the
product to be updated.
Transaction 2 runs in parallel to read the
quantity of the product to be updated.
Transaction 1 updates the product quantity to
reduce it by 100.
Transaction 2 updates the product quantity to
reduce it by 5.
, 6. The product quantity ends
UNIT 3at— MILESTONE 3
195.
16/21
1. A fairly large update is
made to the products table.
2. The update is saved to
the logs.
3. The update starts to then
save to the disk.
4. The system fails midway
through.
5. When the system starts back
up, the committed transactions
that haven't been written to disk
are written.
1. User 1 has $500 in their
online account.
2. User 2 has $300 in their online
account.
3. User 1 sends user 2 $100.
4. User 1 has $400 in
their account.
5. User 2 has $300 in their
account.
5. The transaction is reverted.
1. Transaction 1 reads a
product's cost which is set at
$100.
2. Transaction 1 updates the
product to set the price to
$90.
3. Transaction 2 reads the
same product's cost and sees
$100.
4. Transaction 1 commits the cost.
3
16/2
Sophia Introduction to Relational Databases
1
Milestone_3.
16/21 that's 76%
This Milestone has been retaken.
16 questions were answered correctly. 5 questions were
answered incorrectly.
1
In each milestone, you may want or need to use the database
and query tool to answer some of the questions. We suggest
you open the tool in another browser tab while you are working
on this assessment.
https://postgres.sophia.org/
Which type of backup would result in the fastest to RESTORE?
Nightly backup
Incremental backup
Full backup
, Differential backup
RATIONALE
,Full backups are a full copy of the entire data set. Although they
areUNIT
the best3protection,
— MILESTONEthey are time-consuming and quite large to
3 Incremental backups only back up the data that has changed
store.
since the previous backup, even if it's another incremental backup.
16/2
These file sizes are the smallest out of the lot. Differential backups
1
are similar to incremental backups, but they start with a full
backup and include data since the prior full backup. At most, there
are only 2 backups to restore from.
CONCEPT
Backup Methods
Report an issue with this question
2
In each milestone, you may want or need to use the database
and query tool to answer some of the questions. We suggest
you open the tool in another browser tab while you are working
on this assessment.
https://postgres.sophia.org/
Which of the following scenarios reflects the
durability property?
The product quantity starts at 200.
Transaction 1 runs to read the quantity of the
product to be updated.
Transaction 2 runs in parallel to read the
quantity of the product to be updated.
Transaction 1 updates the product quantity to
reduce it by 100.
Transaction 2 updates the product quantity to
reduce it by 5.
, 6. The product quantity ends
UNIT 3at— MILESTONE 3
195.
16/21
1. A fairly large update is
made to the products table.
2. The update is saved to
the logs.
3. The update starts to then
save to the disk.
4. The system fails midway
through.
5. When the system starts back
up, the committed transactions
that haven't been written to disk
are written.
1. User 1 has $500 in their
online account.
2. User 2 has $300 in their online
account.
3. User 1 sends user 2 $100.
4. User 1 has $400 in
their account.
5. User 2 has $300 in their
account.
5. The transaction is reverted.
1. Transaction 1 reads a
product's cost which is set at
$100.
2. Transaction 1 updates the
product to set the price to
$90.
3. Transaction 2 reads the
same product's cost and sees
$100.
4. Transaction 1 commits the cost.
