RAG 是什麼?為什麼企業導入 AI 都在談「檢索增強生成」

RAG 讓 AI 能根據你自己的資料回答、減少幻覺。這篇用白話解釋它的原理與應用。

What is RAG

RAG (Retrieval-Augmented Generation, retrieval-enhanced generation) is a practice that first finds relevant content from your database/documents and then lets a large language model answer based on this content.

Why it's important

General large models only know what they learned during training, which may be outdated or fabricated (hallucinations). RAG allows AI to "look up information before answering," so it can:

  • Answer based on a company's internal knowledge and latest documents
  • Provide sources and reduce nonsense
  • Update knowledge without retraining the model

Application examples

  • Enterprise internal Q&A and customer service (such as Glean, CustomGPT.ai)
  • Conversing with documents (such as PDF.ai, NotebookLM)
  • Connecting AI to real-time web search (such as Exa)

Building RAG yourself

Developers often use tools like LangChain, Flowise, and Langflow to build RAG applications.

Further reading

To build a customer service chatbot, see Using AI to build a customer service chatbot.

Difference between RAG and "Fine-tuning"

Both can make AI more understanding of your domain, but they differ in approach:

  • RAG: Doesn't modify the model, just "looks up your data" when answering. Updates are immediate, cost-effective, and provide sources.
  • Fine-tuning: Trains the model again with your data, "infusing" knowledge into it. Suitable for changing the model's style or behavior, but costly and cumbersome to update.

For most enterprise knowledge Q&A needs, RAG is usually a more practical starting point.

Three key factors for successful RAG

  1. Data quality: The cleaner and more structured your documents are, the more accurate the answers will be.
  2. Segmentation strategy: Breaking documents into appropriately sized paragraphs directly affects retrieval quality.
  3. Requiring sources: Letting AI cite sources makes it easier to verify and reduces hallucinations.

Using RAG without coding

To create a customer service chatbot that can answer questions based on uploaded documents, use existing tools like Chatbase or CustomGPT.ai, which are based on RAG and require no coding.

Conclusion

RAG is one of the most practical AI technologies for enterprises — enabling AI to answer accurately based on "your data." To get started quickly, use existing tools, or build custom solutions using vector databases and frameworks. For further reading, see Building an enterprise AI knowledge base.

Frequently Asked Questions

RAG 能解決 AI 幻覺嗎?

能大幅降低,因為 AI 是根據檢索到的真實資料回答並可附來源,但仍非 100%。

導入 RAG 一定要重新訓練模型嗎?

不用,RAG 透過外掛你的資料庫即可更新知識,成本遠低於重新訓練。

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