Essential Concepts: DBMS Keys, Constraints, and Relational Model

Posted by on Nov 26, 2025 in Commercialization and Logistics | 0 comments

Understanding Keys in DBMS

A Key in a Database Management System (DBMS) is an attribute or a set of attributes used to uniquely identify each record (tuple) in a table and to maintain relationships between tables.

Types of Database Keys

  1. Super Key

    A set of one or more attributes that can uniquely identify a record in a table.

    Example: Given Student(Roll_No, Name, Email), both {Roll_No} and {Roll_No, Name} are Super Keys.

  2. Candidate Key

    A minimal Super Key, meaning no unnecessary attribute is included.

    Example:

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Essential Concepts in Database Management Systems (DBMS)

Posted by on Oct 20, 2025 in Commercialization and Logistics | 0 comments

Database Administrator (DBA) Functions

A Database Administrator (DBA) is responsible for managing and maintaining the database system. Key functions include:

  • Ensuring data security.
  • Creating and managing user accounts.
  • Managing storage allocation.
  • Performing backups and recovery procedures.
  • Tuning database performance.
  • Maintaining database integrity.

Specialization and Aggregation in ER Modeling

Specialization is the process of dividing an entity into sub-entities based on specific characteristics (e.g.,

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Database Architecture, Data Models, and Relational Algebra

Posted by on Oct 19, 2025 in Commercialization and Logistics | 0 comments

**i) View of Data:**A database has multiple views to cater to different users.It consists of 3 levels:*Internal Level (Physical View):*Defines how data is physically stored on hardware.*Conceptual Level (Logical View):*Represents the entire database structure without storage details.*External Level (User View):*Provides customized views of data for different users,hiding unnecessary details.**ii) Data Abstraction:**Data abstraction simplifies database complexity by hiding lower-
level details.It

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Essential Database and Data Management Concepts

Posted by on Jul 17, 2025 in Commercialization and Logistics | 0 comments

Database Fundamentals

Core Database Terminology

  • Catalog: A set of schemas that constitute the description of a database.
  • Schema: The structure that contains descriptions of objects created by a user (base tables, views, constraints).
  • Data Definition Language (DDL): Commands that define a database, including creating, altering, and dropping tables and establishing constraints.
  • Data Manipulation Language (DML): Commands that maintain and query a database.
  • Data Control Language (DCL): Commands that control
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Database Keys: Super, Candidate, Primary & 3NF Concepts

Posted by on May 7, 2025 in Commercialization and Logistics | 0 comments

Super Key vs. Candidate Key Differences

Understanding the distinctions between Super Keys and Candidate Keys is crucial in database design. Below are their key characteristics:

Super Key Characteristics

  • A Super Key is an attribute (or set of attributes) used to uniquely identify all attributes in a relation.
  • Not all Super Keys can be Candidate Keys.
  • The collection of Super Keys helps establish the criteria for selecting Candidate Keys.
  • In a relation, the number of Super Keys is typically greater than
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SQL and Relational Database Concepts Assessment

Posted by on Mar 31, 2025 in Commercialization and Logistics | 0 comments

SQL and Database Concepts Questions

  1. Which of the following will fix one of the issues with the SQL statement in Figure 1a?
    1. StudentID, CRN AUTO_INCREMENT PRIMARY KEY
    2. PRIMARY KEY (StudentID)
    3. FOREIGN KEY (StudentNum) REFERENCES Housing (DormNum)
    4. (StudentID) AUTO_INCREMENT PRIMARY KEY
    5. DELETE TABLE Students
  2. Which of the following is true about Figure 3?
    1. The tables have too many primary keys (PKs)
    2. It uses Chen’s notation
    3. It uses SQL, not ANSI
    4. It uses Crow’s Foot notation
    5. It is a Database Management System (DBMS)
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