PostgreSQL Pertanyaan dan Jawaban Wawancara
Ques 6. What is a subquery, and how is it different from a JOIN?
A subquery is a query nested within another query, returning a single value or a set of values. JOIN combines rows from two or more tables based on a related column.
Ques 7. How can you optimize a PostgreSQL query for better performance?
Optimization techniques include using indexes, proper query design, and analyzing query execution plans.
Ques 8. What is a stored procedure, and how can you create one in PostgreSQL?
A stored procedure is a set of SQL statements stored in the database and executed as a single unit. You can create one using the CREATE PROCEDURE statement.
Ques 9. Explain the purpose of the EXPLAIN command in PostgreSQL.
The EXPLAIN command shows the execution plan of a statement, helping to optimize queries by revealing how PostgreSQL processes them.
Ques 10. What is a foreign key, and how does it enforce referential integrity?
A foreign key is a field that refers to the primary key in another table. It enforces referential integrity by ensuring that values in the foreign key match values in the referenced table's primary key.
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