مخازن المفتاح والقيمة والمستندات

في هذا الدرس

describe the two most common models.

الموضوعات المخطط لها

• Key-value (Redis, DynamoDB basics): fetch by key; very fast; no query by value unless you build an index.
• Document (MongoDB): JSON-like documents with nested data and flexible fields; indexes on fields; query inside the document.
• Document fits data read as a unit: a review with its comments, a product with attributes.
• Consistency: single-document writes are atomic; cross-document needs transactions or design around them.