---
title: InfluxDB key concepts
description: Concepts related to InfluxDB.
url: https://docs.influxdata.com/influxdb/v2/reference/key-concepts/
estimated_tokens: 753
product: InfluxDB OSS v2
version: v2
---

# InfluxDB key concepts

This page documents an earlier version of InfluxDB OSS. [InfluxDB 3 Core](/influxdb3/core/) is the latest stable version.

#### API token hashing is enabled by default in InfluxDB OSS 2.9.0

Stronger token security: tokens are stored as hashes on disk, so a copy of the database file doesn’t expose usable tokens. Existing tokens are hashed on first startup and the original strings can’t be recovered afterward — **capture any plaintext tokens you still need before you upgrade**.

For more information, see [Token hashing](/influxdb/v2/admin/tokens/#token-hashing).

Before working with InfluxDB 2.9, it’s helpful to learn a few key concepts. Browse the topics and videos below to learn more.

### [InfluxDB data elements](/influxdb/v2/reference/key-concepts/data-elements/)

InfluxDB structures data using elements such as timestamps, field keys, field values, tags, etc.

### [InfluxDB data schema](/influxdb/v2/reference/key-concepts/data-schema/)

InfluxDB uses a tabular data schema for displaying raw data in Data Explorer and for returning query results in annotated CSV syntax.

### [InfluxDB design principles](/influxdb/v2/reference/key-concepts/design-principles/)

Principles and tradeoffs related to InfluxDB design.

[key concepts](/influxdb/v2/tags/key-concepts/)