Database Administration Interview
Sql Question(s) & Actual Evaluation
Please refer to the evaluation for more insight.
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Classification: Database Administration
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Topic(s): Sql
Can you explain the difference between primary key and foreign key in SQL?
Candidate's Answer:Primary key is nothing but a Unique Identification of a table and foreign key is nothing but a primary key of a another table which can be used to combine or related to tables in a database is called as foreign key
Evaluation:Your answer is partially correct, but it could be improved with more detail and clarity.
A primary key is a column (or a combination of columns) that uniquely identifies each row in a table. It must contain unique values and cannot have NULL values. The primary key is used to enforce entity integrity in a database table.
On the other hand, a foreign key is a column (or a set of columns) in a table that references the primary key of another table. It establishes a relationship between the two tables by ensuring referential integrity. This means that the values in the foreign key column must exist in the primary key column of the referenced table or be NULL.
To improve your answer, you can explain the importance of primary and foreign keys in maintaining data integrity in a relational database. You can also provide examples or scenarios where primary and foreign keys are used in SQL to illustrate their significance.
Overall, your answer is clear and provides a basic understanding of primary and foreign keys in SQL. However, adding more detail and examples would further enhance the explanation.
Rating: 3/5
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Classification: Database Administration
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Topic(s): Sql
How do you optimize SQL queries for better performance?
Candidate's Answer:The best face to optimise a query is to removing the unwanted things unwanted patching from the database
Evaluation:Your answer is partially correct, but it lacks specific details on how to optimize SQL queries for better performance. Optimizing SQL queries involves various techniques such as creating indexes on columns frequently used in WHERE clauses, avoiding the use of SELECT * and only selecting the columns needed, using appropriate join types, and minimizing the use of functions in WHERE clauses.
To improve your answer, you could provide a more detailed explanation of these techniques and how they can be applied in optimizing SQL queries for better performance. Additionally, mentioning tools such as query analyzers or profiling tools that can help identify and optimize slow queries would also add value to your response.
Overall, I would rate your answer 2.5/5. With some additional details and explanations, it could definitely be improved to receive a higher rating.