DBMS Review Flashcards

Flashcards for reviewing Database Management Systems concepts.

DBMS

Software that manages data efficiently and securely. Key features include Data Abstraction, Multiple Views, Data Independence, Concurrency Control, Integrity & Security, Recovery & Backup.

Data Abstraction

Hides the complexity of data storage and shows only relevant information to users; includes Physical, Logical, and View Levels.

Multiple Views

Allows different users to access the same database with different perspectives, ensuring role-based access and improved data security and usability.

Data Independence

The ability to change the schema at one level without affecting the schema at the next higher level; includes Logical and Physical Data Independence.

Concurrency Control

Mechanism that allows multiple users to access data simultaneously without conflicts, ensuring data consistency in a multi-user environment using techniques like Locking or Timestamp ordering.

Integrity

Ensures accuracy and consistency of data using rules and constraints (e.g., primary key, foreign key).

Security

Controls who can access or modify the data, including features like Authorization & authentication, Encryption, and Access controls.

Recovery & Backup

Recovery restores the database to a correct state after a failure; Backup creates periodic copies of data to prevent data loss, ensuring data durability and reliability.

Naive User

Interacts with the database through predefined applications without knowledge of database internals or query languages (e.g., ATM users).

Application Programmer

Writes application programs that interact with the database, using APIs or embedded SQL (e.g., Backend developers).

DBA (Database Administrator)

Sets up, configures, and maintains the database system, responsible for security, backup, recovery, tuning, and user management (e.g., IT personnel).

Sophisticated User

Directly interacts with the database using SQL or query tools, performs complex queries, analysis, and reports (e.g., Data analysts).

Internal Schema (Storage Level)

Defines how data is physically stored; Lowest level of abstraction.

Conceptual Schema (Logical Level)

Defines the overall database structure; Middle level of abstraction.

External Schema (View Level)

Defines customized views for different users or applications; Top level of abstraction.

Physical Data Independence

Changes in storage (internal schema) do not affect the conceptual schema.

Logical Data Independence

Changes in the conceptual schema do not affect external views.

Structured Data

Highly organized and follows a predefined schema, stored in relational databases (RDBMS), uses SQL for querying.

Semi-structured Data

Does not follow a strict tabular format but has some organizational elements, uses tags, attributes, or key-value pairs, common in NoSQL databases.

Unstructured Data

Has no predefined format, difficult to store in traditional databases, requires specialized processing techniques (AI, Big Data tools).

Data Model

Describes how data is organized (e.g., Relational, Hierarchical, Network, Object-Oriented).

Schema

Logical definition of DB structure (e.g., External, Conceptual, Internal).

DDL (Data Definition Language)

Used to create and modify schema (e.g., CREATE TABLE).

DML (Data Manipulation Language)

Used to modify data (e.g., INSERT, UPDATE).

DCL (Data Control Language)

Used to control access permissions (e.g., GRANT, REVOKE).

TCL (Transaction Control Language)

Used to manage transactions (e.g., COMMIT, ROLLBACK).

Ternary Relationship

A relationship that involves three entities simultaneously.