What is the main difference between a relational and a NoSQL database?
Relational = structured tables with rows/columns, use SQL, enforce ACID. NoSQL = flexible schema, designed for scale, low-latency, and modern apps (mobile, gaming, IoT).
What does ACID stand for in relational databases?
Atomicity, Consistency, Isolation, Durability.
What is a primary key?
A unique identifier for each row in a relational database table.
What is a foreign key?
A field that links one table to another, establishing relationships between data.
What is Amazon RDS?
A managed relational database service that supports MySQL, PostgreSQL, MariaDB, Oracle, and SQL Server.
Aurora is compatible with which two database engines?
MySQL and PostgreSQL.
What are the main benefits of Amazon Aurora compared to standard MySQL/PostgreSQL?
Up to 3x/5x better performance, 6-way replication across 3 AZs, autoscaling up to 128 TB, automatic failover, and up to 15 read replicas.
What is Amazon DynamoDB?
A fully managed, serverless, NoSQL key-value and document database with single-digit millisecond latency.
What are some DynamoDB key features?
On-demand or provisioned capacity, point-in-time recovery, global tables (multi-region), native encryption (AES-256), integration with Streams, S3 export, Glue, CloudWatch.
Difference between DynamoDB and S3 (data lake)?
DynamoDB = NoSQL database (semi-structured access, key-value/document). S3 = object storage (unstructured, store “blobs” like files).
What is an in-memory database?
A database that stores data in RAM for ultra-fast access, instead of on disk (SSD/HDD).
What is Amazon ElastiCache for Redis?
A fully managed, in-memory key-value store based on Redis, used for caching, leaderboards, session stores, chat apps, and real-time analytics.
What is ephemeral storage in in-memory databases?
Data loss risk if the server crashes, since data lives in RAM (can be mitigated with persistence or replication).
What is AWS Database Migration Service (DMS)?
A service to migrate databases with minimal downtime. Supports homogeneous (Oracle → Oracle) and heterogeneous (Oracle → Aurora) migrations.
What is the AWS Schema Conversion Tool (SCT)?
A tool that converts database schema and code (tables, views, procedures) from one engine to another during heterogeneous migrations.
Difference between EC2-hosted databases and AWS managed databases?
EC2-hosted = you install and manage DB software yourself (IaaS). Managed (RDS, Aurora, DynamoDB, etc.) = AWS handles patches, backups, scaling (PaaS).
What is Amazon Neptune?
A fully managed graph database optimized for highly connected datasets, supporting billions of relationships and fast graph queries.
What are use cases for Amazon Neptune?
Social networking, recommendation engines, knowledge graphs, IT operations, life sciences.
What is the main advantage of graph databases like Neptune?
They model and query complex relationships (nodes & edges) more efficiently than relational joins.
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Migration to the AWS Cloud & Cloud Economics20
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AWS Shared Responsibility & Compliance21
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aws security services20
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Access Management AWS20
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AWS Components & Resources for Security15
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AWS Infrastracture22
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AWS Compute to Edge Services24
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AWS Database Services19
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AWS Network Services24
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AWS Storage Services22
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AWS ML, AI, & Data Analytics23
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AWS Developer Services & Tools22
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AWS Pricing, Billing, Budgeting, & Cost Management21
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Technical & Support Resources at AWS19
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Benefits & Design Principles of the AWS Cloud15
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