NoSQL database types (document, key-value, column, graph) in DBMS Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to identify the NoSQL database type that stores data as JSON-like documents.

DBMS Theory

The NoSQL database type that stores data as documents is called a [1] database.

Drag options to blanks, or click blank then click option'

Adocument

Bkey-value

Cgraph

Dcolumn

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing document databases with key-value stores.

Thinking graph databases store documents.

A document database stores data as JSON-like documents, making it easy to store and query complex data.

2fill in blank

medium

Complete the code to name the NoSQL database type that stores data as pairs of keys and values.

DBMS Theory

A [1] database stores data as simple key and value pairs.

Drag options to blanks, or click blank then click option'

Acolumn

Bkey-value

Cgraph

Ddocument

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing key-value with document databases.

Confusing key-value with column databases.

Key-value databases store data as pairs, where each key maps to a value, like a dictionary.

3fill in blank

hard

Fix the error in the statement about NoSQL database types.

DBMS Theory

A [1] database organizes data in tables with rows and columns, similar to relational databases.

Drag options to blanks, or click blank then click option'

Akey-value

Bdocument

Ccolumn

Dgraph

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing column databases with relational databases.

Thinking graph databases use tables.

Column databases store data in columns and rows but are different from relational databases by focusing on columns for fast queries.

4fill in blank

hard

Fill both blanks to describe the NoSQL database type that stores data as nodes and edges.

DBMS Theory

A [1] database stores data as [2] and edges to represent relationships.

Drag options to blanks, or click blank then click option'

Agraph

Bdocument

Cnodes

Dkey-value

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing graph with document or key-value databases.

Confusing edges with nodes.

Graph databases store data as nodes (entities) and edges (relationships) to model complex connections.

5fill in blank

hard

Fill all three blanks to complete the description of NoSQL database types and their data structures.

DBMS Theory

The [1] database stores data as [2], the [3] database stores data as key-value pairs.

Drag options to blanks, or click blank then click option'

Adocument

Bgraph

Ckey-value

Dnodes

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping graph and key-value database descriptions.

Confusing nodes with key-value pairs.

Document databases store data as documents, graph databases use nodes and edges, and key-value databases store simple key-value pairs.

Practice

1. Which NoSQL database type is best suited for storing data as JSON-like documents with flexible schemas?

easy

A. Graph database

B. Document database

C. Column database

D. Key-value database

Solution

1. Step 1: Understand document database structure

   Document databases store data as documents, often JSON-like, allowing flexible and nested data.

2. Step 2: Compare with other NoSQL types

   Key-value stores use simple key-value pairs, column stores organize data by columns, and graph databases focus on relationships.

3. Final Answer:

   Document database -> Option B

4. Quick Check:

   Flexible JSON-like storage = Document database [OK]

Hint: JSON-like flexible data means document DB [OK]

Common Mistakes:

• Confusing key-value with document stores
• Thinking column stores handle JSON
• Assuming graph DB stores documents

2. Which of the following is the correct way to describe a key-value store?

easy

A. Stores data as nested JSON documents

B. Stores data as interconnected nodes and edges

C. Stores data in tables with rows and columns

D. Stores data as simple pairs of keys and values

Solution

1. Step 1: Define key-value store

   Key-value stores save data as pairs: a unique key and its associated value.

2. Step 2: Eliminate other options

   Nodes and edges describe graph DB, tables describe relational or column DB, nested JSON describes document DB.

3. Final Answer:

   Stores data as simple pairs of keys and values -> Option D

4. Quick Check:

   Key-value = key and value pairs [OK]

Hint: Key-value means simple pairs, not complex structures [OK]

Common Mistakes:

• Mixing graph DB with key-value store
• Confusing column DB with key-value
• Thinking document DB is key-value

3. Given a graph database storing people and their friendships, which query result would you expect from a query asking for all friends of 'Alice'?

medium

A. A set of nodes connected to 'Alice' by edges labeled 'friend'

B. A table with columns for friend names and ages

C. A list of key-value pairs with friend names

D. A JSON document containing Alice's profile

Solution

1. Step 1: Understand graph database query

   Graph DB queries return nodes and edges; friends of Alice are nodes connected by 'friend' edges.

2. Step 2: Compare expected outputs

   Key-value pairs or tables are not typical graph DB outputs; JSON document is for document DB.

3. Final Answer:

   A set of nodes connected to 'Alice' by edges labeled 'friend' -> Option A

4. Quick Check:

   Graph DB returns connected nodes and edges [OK]

Hint: Graph DB queries return nodes and edges, not tables or JSON [OK]

Common Mistakes:

• Expecting tabular output from graph DB
• Confusing document DB JSON with graph DB output
• Thinking key-value pairs represent graph edges

4. You wrote a query to retrieve data from a column-family NoSQL database but got an error. Which mistake likely caused this?

medium

A. Using nested JSON documents in the query

B. Querying nodes and edges instead of tables

C. Trying to access data by key only without specifying column family

D. Using key-value pairs without keys

Solution

1. Step 1: Understand column-family DB query requirements

   Column-family DBs require specifying column families to access data properly.

2. Step 2: Identify error cause

   Accessing data by key alone without column family causes errors; other options relate to different DB types or invalid syntax.

3. Final Answer:

   Trying to access data by key only without specifying column family -> Option C

4. Quick Check:

   Column DB needs column family in queries [OK]

Hint: Column DB queries must specify column family [OK]

Common Mistakes:

• Using document DB JSON syntax in column DB
• Ignoring column family in queries
• Confusing graph DB queries with column DB

5. You need to design a social network app that stores users, their posts, and complex friend relationships with recommendations. Which NoSQL database type should you choose and why?

hard

A. Graph database, because it efficiently manages complex relationships

B. Key-value database, because it is fastest for any data

C. Document database, because it handles nested posts well

D. Column database, because it stores large tables efficiently

Solution

1. Step 1: Analyze app data needs

   The app needs to store users, posts, and complex friend relationships with recommendations.

2. Step 2: Match database type to needs

   Graph DBs excel at managing complex relationships and traversals, ideal for social networks.

3. Step 3: Evaluate other options

   Document DB handles nested data but less efficient for relationships; key-value is simple but not relationship-focused; column DB is for wide tables, not relationships.

4. Final Answer:

   Graph database, because it efficiently manages complex relationships -> Option A

5. Quick Check:

   Complex relationships = Graph DB [OK]

Hint: Complex relationships? Choose graph DB [OK]

Common Mistakes:

• Choosing document DB for relationship-heavy data
• Assuming key-value is best for all speed needs
• Ignoring graph DB strengths in relationships