8.7. SQLAlchemy Core Insert

insert() is a method of a Table object
It could be also used as a object factory

>>> from sqlalchemy import insert

8.7.1. SetUp

>>> from sqlalchemy import create_engine, MetaData, Table, Column
>>> from sqlalchemy import Integer, String, Date, Numeric, Enum
>>> from sqlalchemy import insert
>>>
>>>
>>> engine = create_engine('sqlite:///:memory:', future=True)
>>> metadata = MetaData()
>>>
>>> astronaut = Table('astronaut', metadata,
...     Column('id', Integer, primary_key=True),
...     Column('firstname', String(50), nullable=False),
...     Column('lastname', String(50), nullable=False),
...     Column('agency', Enum('NASA', 'ESA', 'POLSA')),
...     Column('birthdate', Date),
...     Column('age', Integer),
...     Column('height', Numeric(3,2)),
...     Column('weight', Numeric(3,2)),
... )
>>>
>>> with engine.begin() as db:
...     metadata.create_all(db)

8.7.2. Insert Statement

We can insert data using the insert() construct:

>>> query = (
...     insert(astronaut).
...     values(firstname='Mark', lastname='Watney')
... )
>>>
>>> with engine.begin() as db:
...     result = db.execute(query)

We can inspect the query object simply by printing it:

>>> print(query)
INSERT INTO astronaut (firstname, lastname) VALUES (:firstname, :lastname)

8.7.3. Insert Object

The insert() statement, when not given values() will generate the VALUES clause based on the list of parameters that are passed to execute() [1].

Prepare data for insert and execute the query writing it to database:

>>> data = {'firstname': 'Mark', 'lastname': 'Watney'}
>>>
>>> with engine.begin() as db:
...     result = db.execute(astronaut.insert(), data)

8.7.4. Insert List of Objects

Since 1.4/2.0 execute many is greatly improved for PostgreSQL

This format also accepts an 'executemany' style that DBAPI can optimize. Prepare data for insert and execute the query writing it to database [1]:

>>> data = [
...     {'firstname': 'Mark', 'lastname': 'Watney'},
...     {'firstname': 'Melissa', 'lastname': 'Lewis'},
...     {'firstname': 'Rick', 'lastname': 'Martinez'},
... ]
>>>
>>> with engine.begin() as db:
...     result = db.execute(astronaut.insert(), data)

Note, that this is the same .execute() method. SQLAlchemy will recognize that the data is a list[dict] and will execute proper statements to the database.

8.7.5. Recap

insert(table).values()
db.execute(table.insert(), data)
data can be a dict or list[dict]