Key-Value Store

A key-value store is a database model where each item is a unique key mapped to a value, and you read or write the value by supplying its key. The database usually treats the value as opaque data.

Why it matters

The model is simple, so lookups are extremely fast and the data splits cleanly across servers by key. It fits caches, sessions, feature flags, and shopping carts. The limitation is querying: you generally cannot search by value contents or join across items without extra structures you build yourself.

Example

session:9f3a  ->  {"user_id": 42, "expires": 1760000000}
cart:42       ->  [{"sku":"A-100","qty":2}]
flag:new-ui   ->  "true"

Each line is one key and its value.

Common mistakes

• Designing keys with no naming convention, which makes cleanup and debugging painful.
• Trying to run ad hoc queries on values, which this model does not support well.
• Using a hot key that receives most of the traffic and overloads one node.

Related

• Redis
• NoSQL
• Document database

यह पेज सामान्य जानकारी है, जिसे हमारी संपादकीय टीम ने लिखा है और दस्तावेज़ीकरण बदलने पर अपडेट किया जाता है। सर्वर और प्रदाता अलग-अलग होते हैं, इसलिए बदलाव पहले सुरक्षित तरीके से जाँचें। देखें: संपादकीय नीति और अस्वीकरण.