langchain/tests/unit_tests/test_sql_database_schema.py
Francisco Ingham 3f29742adc
Sql alchemy commands used in table info (#1135)
This approach has several advantages:

* it improves the readability of the code
* removes incompatibilities between SQL dialects
* fixes a bug with `datetime` values in rows and `ast.literal_eval`

Huge thanks and credits to @jzluo for finding the weaknesses in the
current approach and for the thoughtful discussion on the best way to
implement this.

---------

Co-authored-by: Francisco Ingham <>
Co-authored-by: Jon Luo <20971593+jzluo@users.noreply.github.com>
2023-02-18 10:58:29 -08:00

77 lines
2.0 KiB
Python

# flake8: noqa
"""Test SQL database wrapper with schema support.
Using DuckDB as SQLite does not support schemas.
"""
from sqlalchemy import (
Column,
Integer,
MetaData,
Sequence,
String,
Table,
create_engine,
event,
insert,
schema,
)
from langchain.sql_database import SQLDatabase
metadata_obj = MetaData()
event.listen(metadata_obj, "before_create", schema.CreateSchema("schema_a"))
event.listen(metadata_obj, "before_create", schema.CreateSchema("schema_b"))
user = Table(
"user",
metadata_obj,
Column("user_id", Integer, Sequence("user_id_seq"), primary_key=True),
Column("user_name", String, nullable=False),
schema="schema_a",
)
company = Table(
"company",
metadata_obj,
Column("company_id", Integer, Sequence("company_id_seq"), primary_key=True),
Column("company_location", String, nullable=False),
schema="schema_b",
)
def test_table_info() -> None:
"""Test that table info is constructed properly."""
engine = create_engine("duckdb:///:memory:")
metadata_obj.create_all(engine)
db = SQLDatabase(engine, schema="schema_a", metadata=metadata_obj)
output = db.table_info
expected_output = """
CREATE TABLE schema_a."user" (
user_id INTEGER NOT NULL,
user_name VARCHAR NOT NULL,
PRIMARY KEY (user_id)
)
SELECT * FROM 'user' LIMIT 3;
user_id user_name
"""
assert sorted(" ".join(output.split())) == sorted(" ".join(expected_output.split()))
def test_sql_database_run() -> None:
"""Test that commands can be run successfully and returned in correct format."""
engine = create_engine("duckdb:///:memory:")
metadata_obj.create_all(engine)
stmt = insert(user).values(user_id=13, user_name="Harrison")
with engine.begin() as conn:
conn.execute(stmt)
db = SQLDatabase(engine, schema="schema_a")
command = 'select user_name from "user" where user_id = 13'
output = db.run(command)
expected_output = "[('Harrison',)]"
assert output == expected_output