Test: Data Storage and Querying - 1 - Software Development MCQ

Primary memory, also known as main memory or RAM, is volatile and provides temporary storage for data and program instructions.

The CPU is not a data storage device. It is the primary component responsible for executing instructions and performing calculations in a computer system.

B-tree indexing is commonly used for fast searching in a database. It organizes data in a balanced tree structure, allowing efficient retrieval based on the indexed key values.

Indexing in a database management system is used to improve data storage efficiency and retrieval speed by creating a separate data structure that enables faster searching and access to specific data.

In a hash table, collisions occur when two different keys hash to the same bucket. A bucket is a container that holds elements with the same hash value.

The code prints the element at index 3 in the list my_list, which is 4.

The code attempts to retrieve the value associated with the key 'gender' from the dictionary my_dict using the get() method. Since the key does not exist in the dictionary, it returns None.

The code adds the value 3 to the set my_set. However, since sets only store unique elements, the duplicate value is not added. Therefore, the length of my_set remains 4.

The code prints a slice of the tuple my_tuple starting from index 1. The slice [1:] includes all elements from index 1 to the end, resulting in (2, 3).

The lower() method is used to convert all characters in a string to lowercase. The code converts the string my_string to lowercase, resulting in "hello, world!".

The code creates a list of department names by extracting the 'department' value from each employee dictionary in the employees list. The department names are then converted into a set to eliminate duplicates. The length of the set department_set is 3.

The code demonstrates hash table implementation using a hash function that performs modulo division. Each key from the keys list is hashed, and the resulting index is used to append the key to the corresponding bucket in the hash_table.

The code creates instances of the Student class and stores them in a dictionary student_dict with the 'roll_number' as the key. The code accesses the student with a roll number of 2 (student_dict[2]) and prints its name, which is 'Emma'.

The code defines a Database class with insert() and search() methods. An instance of the class db is created, and values are inserted into the data list using the insert() method. The search() method is then used to check if the value 20 exists in the data list, returning True.

The code demonstrates hash table implementation using the MD5 hashing algorithm. The hash_string() function converts a string into its MD5 hash. The keys from the keys list are hashed, and the resulting hash values are converted to integers and used as indices to append the keys to the appropriate buckets in the hash_table.