// 所有知识统一为 knowledge_node
CREATE TABLE knowledge_node (
id BIGSERIAL, name VARCHAR(255),
type VARCHAR(50) // VOCABULARY | GRAMMAR | IELTS_TOPIC | TECH_CONCEPT | INTERVIEW_TOPIC | SCENARIO | SKILL
category VARCHAR(100), level INT, description TEXT
);
| type | 示例 | 说明 |
| VOCABULARY | deployment | 技术词汇节点 |
| TECH_CONCEPT | RAG | 技术概念节点 |
| IELTS_TOPIC | Describe a technology | 雅思话题节点 |
| INTERVIEW_TOPIC | System Design Interview | 面试话题节点 |
// 知识关联表
CREATE TABLE knowledge_relation (
source_id BIGINT, target_id BIGINT,
relation_type VARCHAR(50) // RELATED | PARENT | CHILD | USED_IN | REQUIRED_FOR | SIMILAR
);