3i Infotech Placement: Sample Questions 977 - 978 of 1245
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Question 977
Statement True-False▾
A database trigger does not apply to data loaded before the definition of the trigger
Choices
Choice (4) | |
---|---|
a. | True |
b. | False |
c. | Question does not provide sufficient data or is vague |
d. | All of the above |
Answer
b.Explanation
- Database triggers are executed in response to events that occur in the database.
- Like a stored procedure it is predefined before event occurs.
- Enable database administrators to create additional relationships between separate databases.
- It can execute before or after an INSERT, UPDATE, or DELETE operation.
- If a trigger event occurs, the trigger՚s function is called at the appropriate time to handle the event.
- Stored code executed immediately after a predefined event.
- A database trigger does apply to data loaded before the definition of the trigger.
- Mostly used for maintaining the integrity of the information on the database.
Question 978
Explanation
In-Order Traversal:
- The left subtree is visited first, then the root and later the right sub-tree.
- Outputs sorted key values in ascending order.
Algorithm
- Recursively traverses left subtree.
- Visit root node.
- Recursively traverse right subtree.
Pre-order Traversal:
- Root node is visited first, then the left subtree and finally the right subtree.
Algorithm:
- Visit root node.
- Recursively traverse left subtree.
- Recursively traverse right subtree.
Post-order Traversal
- The root node is visited last, hence the name.
- First we traverse the left subtree, then the right subtree and finally the root node.
Algorithm:
- Recursively traverse left subtree.
- Recursively traverse right subtree.
- Visit root node.