# VectorDBQA

> **Class** in `langchain_classic`

📖 [View in docs](https://reference.langchain.com/python/langchain-classic/chains/retrieval_qa/base/VectorDBQA)

Chain for question-answering against a vector database.

## Signature

```python
VectorDBQA()
```

## Extends

- `BaseRetrievalQA`

## Properties

- `vectorstore`
- `k`
- `search_type`
- `search_kwargs`

## Methods

- [`validate_search_type()`](https://reference.langchain.com/python/langchain-classic/chains/retrieval_qa/base/VectorDBQA/validate_search_type)

## ⚠️ Deprecated

Deprecated since version 0.2.13.

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[View source on GitHub](https://github.com/langchain-ai/langchain/blob/6fb37dba71da807af60aa7b909f71f0625a666bf/libs/langchain/langchain_classic/chains/retrieval_qa/base.py#L298)