first()

The first() method returns the first record from the query. It is similar to applying LIMIT 1 at the end of the SQL query. In the output, we can see that we were able to fetch a record from the table. However, if we try to iterate through the result we get an error that the object is not iterable, the reason being there is only one record present in the result.

Syntax: sqlalchemy.engine.Result.first()

Fetch the first row or None if no row is present. Closes the result set and discards remaining rows.

Python

from sqlalchemy.orm import sessionmaker
import sqlalchemy as db
from sqlalchemy.ext.declarative import declarative_base
 
Base = declarative_base()
 
# DEFINE THE ENGINE (CONNECTION OBJECT)
engine = db.create_engine(
    "mysql+pymysql://root:password@localhost/Geeks4Geeks")
 
# CREATE THE TABLE MODEL TO USE IT FOR QUERYING
class Profile(Base):
 
    __tablename__ = 'profile'
 
    email = db.Column(db.String(50), primary_key=True)
    name = db.Column(db.String(100))
    contact = db.Column(db.Integer)
 
 
class Students(Base):
 
    __tablename__ = 'students'
 
    first_name = db.Column(db.String(50), primary_key=True)
    last_name = db.Column(db.String(50), primary_key=True)
    course = db.Column(db.String(50), primary_key=True)
    score = db.Column(db.Float)
 
 
# CREATE A SESSION OBJECT TO INITIATE QUERY IN DATABASE
Session = sessionmaker(bind=engine)
session = Session()
 
# SELECT * FROM profile LIMIT 1
result = session.query(Profile).first()
 
print(result.email, "|", result.name, "|", result.contact)
 
# VIEW THE ENTRIES IN THE RESULT
for r in result:
    print(r.email, r.name, r.contact)

Output:

SQLAlchemy ORM – Query

In this article, we will see how to query using SQLAlchemy ORM in Python.

To follow along with this article, we need to have sqlalchemy and anyone database installed in our system. We have used the MySQL database for this article’s understanding.

Created a Profile table and a Students table:

Here we are going to cover the following methods:

add_columns()
add_entity()
count()
delete()
distinct()
filter()
get()
first()
group_by()
join()
one()

first()

Python

SQLAlchemy ORM – Query

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