PostgreSQL, often referred to as Postgres, is a powerful open-source relational database management system (RDBMS) known for its scalability, robustness, and extensibility. It offers advanced features like ACID compliance, support for complex data types, and support for both SQL and NoSQL data. PostgreSQL is highly regarded for its performance, security, and reliability, making it a popular choice for applications ranging from small startups to large enterprises. Its active developer community continuously enhances and maintains the software. PostgreSQL is an excellent choice for data storage, analysis, and management in various domains, including web applications, data warehousing, and geospatial applications.
61. In PostgreSQL, which statement is used to insert data into a table?
62. What is the purpose of the "UPDATE" statement in PostgreSQL?
Answer:To modify existing records in a table
63. What does the "DELETE" statement in PostgreSQL do?
Answer:Removes records from a table
64. In PostgreSQL, which clause is used to filter the result set of a SELECT statement?
65. What is the purpose of the "COMMIT" statement in PostgreSQL transactions?
Answer:To permanently save changes to the database
66. What is a PostgreSQL transaction?
Answer:A sequence of one or more SQL statements treated as a single unit of work
67. What is the role of the "ROLLBACK" statement in PostgreSQL transactions?
Answer:To undo changes made during a transaction and restore the original state
68. In PostgreSQL, what does the "SAVEPOINT" statement do within a transaction?
Answer:Sets a point within a transaction to which you can later roll back
69. What does the "BEGIN" statement do in PostgreSQL transactions?
Answer:Initiates a new transaction
70. In PostgreSQL, what is a "nested transaction"?