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langchain/libs
Bae-ChangHyun a2863f8757 community: add 'get_col_comments' option for retrieve database columns comments (#30646)
## Description
Added support for retrieving column comments in the SQL Database
utility. This feature allows users to see comments associated with
database columns when querying table information. Column comments
provide valuable metadata that helps LLMs better understand the
semantics and purpose of database columns.

A new optional parameter `get_col_comments` was added to the
`get_table_info` method, defaulting to `False` for backward
compatibility. When set to `True`, it retrieves and formats column
comments for each table.

Currently, this feature is supported on PostgreSQL, MySQL, and Oracle
databases.

## Implementation
You should create Table with column comments before.

```python
db = SQLDatabase.from_uri("YOUR_DB_URI")
print(db.get_table_info(get_col_comments=True)) 
```
## Result
```
CREATE TABLE test_table (
	name VARCHAR
        school VARCHAR)
/*
Column Comments: {'name': person name, 'school":school_name}
*/

/*
3 rows from test_table:
name
a
b
c
*/
```

## Benefits
1. Enhances LLM's understanding of database schema semantics
2. Preserves valuable domain knowledge embedded in database design
3. Improves accuracy of SQL query generation
4. Provides more context for data interpretation

Tests are available in
`langchain/libs/community/tests/test_sql_get_table_info.py`.

---------

Co-authored-by: chbae <chbae@gcsc.co.kr>
Co-authored-by: Chester Curme <chester.curme@gmail.com>
2025-04-28 15:19:46 +00:00
..
2025-04-24 13:22:31 -04:00