Database Management Systems

Step 1: Understand structured vs unstructured data.
- Structured Data: Organized in rows and columns (e.g., databases, spreadsheets).
- Unstructured Data: Not organized in a predefined format (e.g., videos, images, audio).
- Ambiguous data: Not a standard category in data classification.
- Formal data: Not a recognized data type in this context.

Step 2: Apply to scenario.
Video recording produces raw media files with no tabular structure → Unstructured data.
Final Answer:

A relational database stores data in a structured format using tables, with rows representing records and columns representing attributes of those records. These tables can be linked using keys, making relational databases highly efficient for managing and querying data.
- Data stored in key-value pairs (A) is a characteristic of NoSQL databases, such as key-value stores.
- Data stored in a hierarchical structure (C) is characteristic of hierarchical databases, which organize data in a tree-like structure.
- Data stored as a graph (D) refers to graph databases, which represent data as nodes and edges.
Therefore, the correct answer is (B), relational databases use tables to store data.

SQL stands for Structured Query Language, which is a standardized programming language used to manage and manipulate relational databases. It allows for querying, inserting, updating, and deleting data in a database.
- System Query Language (A) is incorrect as SQL refers to Structured Query Language, not system-specific queries.
- Sequential Query Logic (C) is not related to SQL, as it does not define the core functionality of SQL.
- Standard Query Layer (D) is also incorrect, as SQL is specifically about querying databases, not a "query layer."
Therefore, the correct answer is (B), Structured Query Language.

The four main types of database models are:
- Relational (A): In this model, data is organized into tables (or relations), with relationships between the tables defined by foreign keys.
- Hierarchical (B): This model organizes data in a tree-like structure, where each record has a parent-child relationship.
- Network (C): In this model, data is organized in a graph format, where nodes represent data entities, and edges represent relationships between them.
- Sequential (D) is NOT a recognized database model. It refers to a method of data access in which records are processed in a sequential order, typically in a flat-file database, but not a database model type.
Therefore, the correct answer is (D).