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Is it possible to do SELECT * in SQLAlchemy?
Specifically, SELECT * WHERE foo=1?
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The select() method of table object enables us to construct SELECT expression. The resultant variable is an equivalent of cursor in DBAPI. We can now fetch records using fetchone() method. Here, we have to note that select object can also be obtained by select() function in sqlalchemy.
Python Flask and SQLAlchemy ORM All SELECT statements generated by SQLAlchemy ORM are constructed by Query object. It provides a generative interface, hence successive calls return a new Query object, a copy of the former with additional criteria and options associated with it.
Lazy loading refers to objects are returned from a query without the related objects loaded at first. When the given collection or reference is first accessed on a particular object, an additional SELECT statement is emitted such that the requested collection is loaded.
Is no one feeling the ORM love of SQLALchemy today? The presented answers correctly describe the lower level interface that SQLAlchemy provides. Just for completeness this is the more-likely (for me) real-world situation where you have a session instance and a User class that is orm mapped to the users table.
for user in session.query(User).filter_by(name='jack'): print user # ... And this does an explicit select on all columns.
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The following selection works for me in the core expression language (returning a RowProxy object):
foo_col = sqlalchemy.sql.column('foo') s = sqlalchemy.sql.select(['*']).where(foo_col == 1) If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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