No SQL

Firestore and Bigtable Basics

A comparison of Google Cloud's two flagship NoSQL databases: Firestore for flexible document data and Bigtable for massive-scale wide-column workloads.

SQL vs NoSQL

A balanced comparison of relational and NoSQL databases, covering when each model fits and the major NoSQL categories.

SQL vs NoSQL Cloud Databases

Understand the practical differences between relational (SQL) and NoSQL databases and when to choose each in the cloud.

SQL vs NoSQL Tradeoffs

Compares relational and non-relational databases across schema flexibility, consistency, scalability, and query capability to guide selection for a given workl…

Difference Between SQL and NoSQL Databases

SQL databases are relational, store data in structured tables with a fixed schema, and use SQL for querying; NoSQL databases are non-relational, store data in…

What is CAP Theorem?

CAP theorem states that a distributed data store can only guarantee two of three properties at once — Consistency, Availability, and Partition tolerance — duri…

What is the Document Database Model?

A document database stores each record as a self-contained, semi-structured document, typically JSON or BSON, where related fields and nested data live togethe…

What is a Column-Family Database Model?

A column-family database groups related columns into named families and stores each row's data physically by column family rather than by row, so queries touch…

What is the Graph Database Model?

A graph database stores data as nodes (entities) and edges (relationships between them), both of which can carry properties, and it is optimized to traverse re…

What is a Key-Value Store and When Should You Use One?

A key-value store is the simplest NoSQL model: every item is an opaque value retrieved by a unique key, with no required schema and no built-in support for que…

Wide-Column Store vs Relational Database: What is the Difference?

A wide-column store lets each row hold millions of dynamically named, sparse columns grouped by family and distributed by row key across many nodes, while a re…

How Do You Design Document Schemas in MongoDB?

MongoDB document schema design means choosing, for each relationship in your data, whether to embed related data inside a single document or reference it from…

What Are the Basics of Cassandra Data Modeling?

Cassandra data modeling means designing tables around the exact queries your application will run, since Cassandra has no joins and limited ad-hoc filtering, s…

What Data Structures Does Redis Support and When to Use Them?

Redis is an in-memory key-value store whose values can be rich data structures — strings, hashes, lists, sets, sorted sets, and streams — each offering differe…

What Are the Basics of Graph Queries in Neo4j?

Neo4j stores data as nodes (entities) and relationships (typed, directed connections between them), and Cypher, its query language, lets you match patterns of…

How Do You Design a Good Partition Key in DynamoDB?

A good DynamoDB partition key spreads items as evenly as possible across the table's underlying partitions by having high cardinality and uniform access freque…

What is Eventual Consistency in Databases?

Eventual consistency is a consistency model where, after writes stop arriving, all replicas of a piece of data are guaranteed to converge to the same value eve…

Strong Consistency vs Eventual Consistency: What is the Difference?

Strong consistency guarantees that any read immediately after a write returns that write's value everywhere, while eventual consistency allows reads to briefly…

What is Tunable Consistency and the N/R/W Quorum Model in NoSQL?

Tunable consistency lets a distributed NoSQL store trade consistency for availability and latency per-request, using three configurable numbers: N (replicas ho…

What is a Global Secondary Index (GSI) in DynamoDB?

A Global Secondary Index (GSI) in DynamoDB is an alternate partition-and-sort-key view of a table that lets you query items efficiently by attributes other tha…

How Do Consistency Levels Work in Apache Cassandra?

A Cassandra consistency level (like ONE, QUORUM, or ALL) is a per-query setting that determines how many replica nodes must respond before a read or write is c…

How Does the MongoDB Aggregation Pipeline Work?

The MongoDB aggregation pipeline processes documents through an ordered sequence of stages, each transforming the stream of documents (filtering, reshaping, gr…

How Does MongoDB Sharding Architecture Work?

MongoDB sharding distributes a collection’s documents across multiple shards (each a replica set) using a shard key, coordinated by lightweight mongos routers…

What is an LSM-Tree and How Does it Handle Writes?

A Log-Structured Merge-tree (LSM-tree) is a storage engine design that turns random writes into fast sequential appends by first buffering writes in an in-memo…

SQL vs NoSQL for Scale: Which Should You Choose?

SQL databases scale best when data is relational and consistency matters, typically via vertical scaling or read replicas, while NoSQL databases are built to s…

What is Eventual Consistency?

Eventual consistency is a consistency model in which, if no new updates are made to a piece of data, all replicas will converge to the same value over time, th…

ACID vs BASE: What’s the Difference and When Does Each Apply?

ACID (Atomicity, Consistency, Isolation, Durability) describes transactions that are all-or-nothing, always valid, isolated from each other, and permanently sa…