I'm using Flask-SQLAlchemy to query from a database of users; however, while
user = models.User.query.filter_by(username="ganye").first()
will return
<User u'ganye'>
doing
user = models.User.query.filter_by(username="GANYE").first()
returns
None
I'm wondering if there's a way to query the database in a case insensitive way, so that the second example will still return
<User u'ganye'>
You can do it by using either the lower or upper functions in your filter:
from sqlalchemy import func
user = models.User.query.filter(func.lower(User.username) == func.lower("GaNyE")).first()
Another option is to do searching using ilike instead of like:
.query.filter(Model.column.ilike("ganye"))
Improving on @plaes's answer, this one will make the query shorter if you specify just the column(s) you need:
user = models.User.query.with_entities(models.User.username).\
filter(models.User.username.ilike("%ganye%")).all()
The above example is very useful in case one needs to use Flask's jsonify for AJAX purposes and then in your javascript access it using data.result:
from flask import jsonify
jsonify(result=user)
you can do
user = db.session.query(User).filter_by(func.lower(User.username)==func.lower("GANYE")).first()
Or you can use ilike function
user = db.session.query(User).filter_by(User.username.ilike("%ganye%")).first()
I think the best solution would be
func.lower(User.username).contains(username.lower())
It will produce sql like
WHERE (lower(user.username) LIKE '%%' || %s || '%%')
This means your db username will be converted to the lower case and your python value username also will be converted to lower case. So now you do not have to worry about the case sesitivity
If your username is Sara Smith It will work for ara, sar, Sara or event a S
from sqlalchemy.sql import func to get the aforementioned func. –
Silurid If it fits your use case, you may consider setting a custom collation on the column, such that the column automatically handles comparisons in a case-insensitive manner.
It's worth noting:
ORDER BY clauses as wellin other words, consult your RDBMS's docs before using this feature.
This example script shows how you might use collations for MySQL, Postgresql (note the special-casing) and Sqlite; each RDBMS returns all three possible results for the query value.
import sqlalchemy as sa
from sqlalchemy import orm
data = {
'mysql': ('mysql:///test', 'utf8mb4_general_ci'),
'postgresql': ('postgresql:///test', 'coll'),
'sqlite': ('sqlite://', 'NOCASE'),
}
for dialect, (uri, collation) in data.items():
Base = orm.declarative_base()
class Test(Base):
__tablename__ = 't16573095'
id = sa.Column(sa.Integer, primary_key=True)
name = sa.Column(sa.String(32, collation=collation))
engine = sa.create_engine(uri, echo=False, future=True)
Base.metadata.drop_all(engine)
if dialect == 'postgresql':
# Postgres collations are more complicated
# - read the docs!
with engine.begin() as conn:
conn.execute(sa.text('DROP COLLATION IF EXISTS coll'))
stmt = """CREATE COLLATION coll (provider='icu', locale='und-u-ks-level2', deterministic=false)"""
conn.execute(sa.text(stmt))
Base.metadata.create_all(engine)
Session = orm.sessionmaker(engine, future=True)
with Session.begin() as s:
instances = [Test(name=name) for name in ['GANYE', 'ganye', 'gAnYe']]
s.add_all(instances)
with Session() as s:
results = s.execute(sa.select(Test.name).where(Test.name == 'GaNyE')).scalars()
print(f'{dialect:-<12}')
for name in results:
print(name)
print('-' * 12)
To specify a collation in a query, use an attribute's collate method:
with Session() as s:
query = sa.select(Test).where(Test.name.collate('coll') == 'GaNyE')
results = s.execute(query)
For declarative users, the equivalent without using query is the ColumnOperators.ilike method:
class User(DeclarativeBase):
username: str
req = select(User).where(User.username.ilike("GANYE"))
result = session.execute(req)
will render as lower(User.username) LIKE lower("GANYE")
This is still the case in SQLAlchemy 2.0, and is compatible with AsyncSession, for those using it.
uname = "ganye"
user = models.User.query.filter(User.username.ilikef(f"%{uname}%").first()
return db.session.query(Post).filter(
Post.title.ilike(f"%{search_query}%")
| Post.body.ilike(f"%{search_query}%")
)
Best way is to use case insensitive contains function ie: .icontains(). Example:
.query.filter(Model.column.icontains("search_query"))
cause you are not sure if the user is going to provide the exact text you want to compare with, so using icontains will return a result(s) even if the user query does not contain the EXACT word or phrase he/she is searching for.
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filter_bymethod where the username column is indexed? – Lowerclassman