Explain Logseq DB Concept

Provide a detailed explanation of Logseq DB schema concepts, terminology, or architecture.

Input: $ARGUMENTS

Core Concepts to Explain

Data Model

• Nodes - Unified concept for pages and blocks
• Datascript - The underlying database engine
• EAV Model - Entity-Attribute-Value structure
• Schema - Attribute definitions and constraints

Entity Types

• Pages - Top-level named entities
• Blocks - Content units within pages
• Classes - Tags/supertags with properties
• Properties - Typed key-value metadata
• Journals - Date-based pages

Schema Components

• Attributes - :db/ident, :db/valueType, :db/cardinality
• Types - :default, :number, :date, :checkbox, :url, :node
• Cardinality - :one vs :many
• Validation - Malli schemas

Relationships

• References - :block/refs, :block/tags
• Hierarchy - :block/parent, :block/page
• Inheritance - :logseq.property.class/extends

Queries

• Datalog - Query language
• Pull syntax - Entity retrieval
• Rules - Reusable query logic
• Aggregations - count, sum, avg, etc.

Explanation Format

## [Concept Name]

### What It Is
[Clear, concise definition]

### Why It Matters
[Practical importance in Logseq]

### Technical Details
[Schema representation, code examples]

### How to Use It
[Practical examples in Logseq UI and API]

### Common Patterns
[Typical use cases]

### Related Concepts
- [Related 1] - [brief connection]
- [Related 2] - [brief connection]

### MD vs DB Differences
| Aspect | MD Version | DB Version |
|--------|------------|------------|
| ... | ... | ... |

### Examples

**In UI:**
[How it appears/works in Logseq UI]

**In Datalog:**
\`\`\`clojure
[query example]
\`\`\`

**In Plugin:**
\`\`\`javascript
[API example]
\`\`\`

### Gotchas
- [Common mistake 1]
- [Common mistake 2]

### Further Reading
- [Resource 1]
- [Resource 2]

Quick Reference Topics

If concept is unclear, offer these options:

Category	Topics
Basics	nodes, pages, blocks, properties, tags
Schema	datascript, attributes, types, cardinality
Classes	inheritance, schema-classes, built-in classes
Properties	types, closed-values, namespaces
Queries	datalog, pull, rules, aggregations
Migration	MD vs DB, import, export
Plugins	API, block properties, queries

Explain: $ARGUMENTS