# sql

*author: junjie.jiang*


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## Desription

Read data from sqlite or mysql.

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## Code Example

### Example

```python

from towhee import DataLoader, pipe, ops
p = (
    pipe.input('image_path')
        .map('image_path', 'image', ops.image_decode.cv2())
            .map('image', 'vec', ops.image_embedding.timm(model_name='resnet50'))
                .output('vec')

)


# table cols: id, image_path, label

for data in DataLoader(ops.data_source.sql('sqlite:///./sqlite.db', 'image_table'), parser=lambda x: x[1]):
    print(p(data).to_list(kv_format=True))

# batch
for data in DataLoader(ops.data_source.sql('sqlite:///./sqlite.db', 'image_table'), parser=lambda x: x[1], batch_size=10):
    p.batch(data)
```

**Parameters:**


***sql_url:*** *str*

the url of the sql database for cache, such as '<db_type>+<db_driver>://<username>:<password>@<host>:<port>/<database>'

sqlite: sqlite:///./sqlite.db

mysql: mysql+pymysql://root:123456@127.0.0.1:3306/mysql


***table_name:*** *str*

table name

***cols:*** *str*

The columns to be queried, default to *, indicating all columns

If you want to query specific columns, use the column names and separate them with `,`, such as 'id,image_path,label'


***where:*** *str*

Where conditional statement, for example: id > 100

***limit:*** *int*

The default value is 500. If set to None, all data will be returned.



# More Resources

- [Zilliz attended VLDB Workshop 2021 - Zilliz blog](https://zilliz.com/blog/zilliz-attended-vldb-workshop-2021): Applied ML & AI for Database Systems and Application
- [Vector Database Comparison](https://zilliz.com/comparison): Compare any vector database to an alternative by architecture, scalability, performance, use cases and costs.
- [Database Evolution Journey from Rows and Columns to Vectors - Zilliz blog](https://zilliz.com/learn/from-sql-and-nosql-to-vectors-database-evolution-journey): From structured SQL  and NoSQL and cutting-edge vector databases, this journey undertakes a significant transformation in data management strategies.
- [Vector Database Stories](https://zilliz.com/blog): The Zilliz blog includes technical tutorials, customer stories, and industry developments related to the world's most advanced vector database.
- [Choosing Between Relational and Vector Databases - Zilliz blog](https://zilliz.com/blog/relational-databases-vs-vector-databases): Learn how to choose between relational and vector databases for your application by understanding the strengths of each.
- [About Zilliz | Zilliz](https://zilliz.com/authors/Zilliz): Vector database