Explanation:A digital signature is a cryptographic mechanism used to verify the authenticity and integrity of a digital message or document. Digital signatures use asymmetric encryption algorithms, where the sender signs the message using their private key, and the receiver verifies it using the sender’s public key. Digital signatures are widely used in secure email communication,…
Explanation:A cryptographic hash function is a mathematical algorithm that takes an input and produces a fixed-size string, typically a hash value or message digest. These functions are deterministic, meaning the same input will always produce the same output. They are used in data integrity checks, digital signatures, and password storage. Properties such as collision resistance,…
A file system is the method and structure by which an operating system manages, stores, and organizes data on storage devices. It provides an interface for users and applications to create, read, write, and manage files on disks. A File System is a method for storing and organizing computer files and the data within them.…
A foreign key constraint enforces referential integrity by linking a column in one table to the primary key of another table. Explanation: Example SQL Foreign Key Constraint: sqlCopyEditCREATE TABLE Employees ( emp_id INT PRIMARY KEY, dept_id INT, FOREIGN KEY (dept_id) REFERENCES Departments(dept_id) ON DELETE SET NULL ); Here, if a department is deleted, dept_id in…
Data redundancy occurs when the same piece of data is stored multiple times in a database. Explanation:
Referential integrity ensures that relationships between tables remain consistent by enforcing foreign key constraints. Explanation: Example SQL Enforcing Referential Integrity: sqlCopyEditCREATE TABLE Orders ( order_id INT PRIMARY KEY, customer_id INT, FOREIGN KEY (customer_id) REFERENCES Customers(customer_id) ON DELETE CASCADE ); Here, if a customer is deleted, all their orders are automatically deleted (ON DELETE CASCADE).
A composite key is a primary key that consists of two or more attributes that uniquely identify a record. Explanation: Example SQL Composite Key: sqlCopyEditCREATE TABLE Enrollment ( student_id INT, course_id INT, enrollment_date DATE, PRIMARY KEY (student_id, course_id) ); Here, student_id and course_id together form a composite key.
A candidate key is an attribute (or set of attributes) that can uniquely identify each tuple in a table. Explanation: Example: For a Students table: student_id email name 101 alice@email.com Alice Here, student_id and email are candidate keys, as both uniquely identify a student.
A tuple is a single record (row) in a relational database table. Explanation: Example: For the Employees table: emp_id name dept_id 1 Alice 10 The row (1, Alice, 10) is a tuple.
A schema is the logical structure of a database, defining tables, columns, relationships, constraints, and indexes. Explanation: Example Schema Definition in SQL: sqlCopyEditCREATE SCHEMA School; CREATE TABLE School.Students ( student_id INT PRIMARY KEY, name VARCHAR(50), age INT ); Here, we created a schema named School and a table Students within it.