```
import requests
import sqlite3
from sqlalchemy import create_engine, Column, Integer, String, Float
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base

# Define the database connection URL
DATABASE_URI = 'sqlite:///coinbase.db'

# Define the SQLAlchemy engine and session
engine = create_engine(DATABASE_URI)
Session = sessionmaker(bind=engine)
session = Session()

# Define the SQLAlchemy Base class
Base = declarative_base()

# Define the schema for the table
class CoinbaseData(Base):
    __tablename__ = 'coinbase_data'
    id = Column(Integer, primary_key=True)
    currency_pair = Column(String)
    exchange_rate = Column(Float)

# Define the Coinbase API URL
url = 'https://api.coinbase.com/v2/exchange-rates'

# Retrieve data from the Coinbase API
response = requests.get(url)
data = response.json()

# Loop through the data and create a new object of CoinbaseData class for each currency pair
for currency_pair, exchange_rate in data['data'].items():
    coinbase_data = CoinbaseData(currency_pair=currency_pair, exchange_rate=float(exchange_rate))
    session.add(coinbase_data)

# Commit the transactions and close the session
session.commit()
session.close()
```
```
import requests
import sqlite3
from sqlalchemy import create_engine, Column, Integer, String, Float
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base

# Define the database connection URL
DATABASE_URI = 'sqlite:///coinbase.db'

# Define the SQLAlchemy engine and session
engine = create_engine(DATABASE_URI)
Session = sessionmaker(bind=engine)
session = Session()

# Define the SQLAlchemy Base class
Base = declarative_base()

# Define the schema for the table
class CoinbaseData(Base):
    __tablename__ = 'coinbase_data'
    id = Column(Integer, primary_key=True)
    currency_pair = Column(String)
    exchange_rate = Column(Float)

# Define the Coinbase API URL
url = 'https://api.coinbase.com/v2/exchange-rates'

# Retrieve data from the Coinbase API
response = requests.get(url)
data = response.json()

# Loop through the data and create a new object of CoinbaseData class for each currency pair
for currency_pair, exchange_rate in data['data'].items():
    coinbase_data = CoinbaseData(currency_pair=currency_pair, exchange_rate=float(exchange_rate))
    session.add(coinbase_data)

# Commit the transactions and close the session
session.commit()
session.close()
```