PostgreSQL Questions et reponses d'entretien
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Question 1. What is PostgreSQL, and how does it differ from other relational database systems?
PostgreSQL is an open-source relational database management system (RDBMS). It differs from others by its extensibility and support for SQL and procedural languages.
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Question 2. Explain the concept of ACID properties in the context of databases.
ACID stands for Atomicity, Consistency, Isolation, and Durability, ensuring the reliability of database transactions.
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Question 3. What is the purpose of the WHERE clause in a PostgreSQL query?
The WHERE clause filters records based on a specified condition, allowing selective data retrieval.
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Question 4. Describe the role of the PRIMARY KEY constraint in PostgreSQL.
The PRIMARY KEY constraint uniquely identifies each record in a table and ensures data integrity.
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Question 5. Explain the difference between INNER JOIN and LEFT JOIN in PostgreSQL.
INNER JOIN retrieves rows where there is a match in both tables, while LEFT JOIN retrieves all rows from the left table and matching rows from the right table.
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Les plus utiles selon les utilisateurs :
- Explain the concept of ACID properties in the context of databases.
- What is the purpose of the WHERE clause in a PostgreSQL query?
- What is a foreign key, and how does it enforce referential integrity?
- Explain the purpose of the SERIAL data type in PostgreSQL.