Database (DBMS) Quiz 2

The correct SQL syntax for granting privileges is GRANT [privileges] ON [object] TO [user]. Option D follows this structure correctly with placeholders for the relation name and username. Options A, B, C, and E have the keywords WHERE and FROM in wrong positions - WHERE and FROM are clauses used in SELECT/UPDATE queries, not in GRANT statements.

The DISTINCT keyword in SQL is used within a SELECT statement to filter out duplicate rows from the result set, returning only unique values. Keywords like 'INDIVIDUAL' or 'SEPARATE' are not valid SQL syntax for this purpose.

ACID is an acronym representing the four key properties of a reliable database transaction: Atomicity (all or nothing), Consistency (valid state transitions), Isolation (independent execution), and Durability (permanent storage). Since all listed options are parts of ACID, 'All of the above' is correct.

In JDBC, a Connection object represents a single session with a specific database. An opened connection is required to execute SQL statements and transactions. A thread is a Java execution thread, not a database session concept. A closed connection cannot execute operations. A pipe is not a JDBC concept.

The CASCADE option in a DROP SCHEMA statement instructs the database to remove the schema along with all of its contained objects (tables, views, etc.) in one operation. RESTRICT would prevent the deletion if any objects still existed within that schema.

Concurrency control in DBMS involves both the Transaction Manager (coordinates transactions, ensures ACID properties) and Lock Manager (manages lock acquisition/release for concurrent access). The Process Manager handles process scheduling, and Cache Manager handles buffer management - neither directly handles concurrency control.

All four statements are valid DDL (Data Definition Language) commands. CREATE SCHEMA defines a namespace, CREATE TABLE defines table structure, CREATE DOMAIN defines a custom data type, and CREATE INDEX builds an index. DDL commands define database structures, not manipulate data.

The RESTRICT keyword in a DROP SCHEMA statement ensures that the schema is only deleted if it contains no objects. If the schema is not empty, the command will fail. In contrast, CASCADE would delete the schema and all objects within it automatically.

A two-phase commit (2PC) is a distributed algorithm that ensures all participating nodes in a database transaction either commit or roll back. This atomicity allows the system to return to a consistent pre-transaction state if an error occurs during any part of the process.

The Connection object in JDBC can create Statement (simple SQL), PreparedStatement (parameterized SQL for reuse), and CallableStatement (for stored procedures). SQLStatement is not a standard JDBC interface. The methods are createStatement(), prepareStatement(), and prepareCall() respectively.