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Lära Challenge: Creating After Trigger | Some Additional Topics
Advanced Techniques in SQL
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Advanced Techniques in SQL

Advanced Techniques in SQL

1. ACID
2. Query optimization.Indexes
3. Some Additional Topics

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Challenge: Creating After Trigger

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Swipe to start coding

Now we will create a trigger to execute after updating the balance column of the BankAccounts table.
When triggered, it will invoke the function after_update_balance(), which logs the account number and the new balance into the UserLogs table, providing a record of balance modifications. The key idea is that we don't have to manually fill in the logs table - it will be done automatically by the trigger.

Note

Pay attention that triggers created for UPDATE operations can be designed to work only for update of the particular column. We can use the following statement to achive this:
CREATE TRIGGER trigger_name AFTER UPDATE OF col_name ON table_name.

Your task is to:

  • Create the after_update_balance() function. It should return a trigger as its result and perform the necessary action, which is updating logs.
  • Create an AFTER UPDATE trigger on the bankaccounts table. This trigger should use the designed function by executing it on each row of the update statement.

Lösning

Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 3. Kapitel 2
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book
Challenge: Creating After Trigger

Uppgift

Swipe to start coding

Now we will create a trigger to execute after updating the balance column of the BankAccounts table.
When triggered, it will invoke the function after_update_balance(), which logs the account number and the new balance into the UserLogs table, providing a record of balance modifications. The key idea is that we don't have to manually fill in the logs table - it will be done automatically by the trigger.

Note

Pay attention that triggers created for UPDATE operations can be designed to work only for update of the particular column. We can use the following statement to achive this:
CREATE TRIGGER trigger_name AFTER UPDATE OF col_name ON table_name.

Your task is to:

  • Create the after_update_balance() function. It should return a trigger as its result and perform the necessary action, which is updating logs.
  • Create an AFTER UPDATE trigger on the bankaccounts table. This trigger should use the designed function by executing it on each row of the update statement.

Lösning

Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 3. Kapitel 2
Switch to desktopByt till skrivbordet för praktisk övningFortsätt där du är med ett av alternativen nedan
Vi beklagar att något gick fel. Vad hände?
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