SQLAlchemy: insert record if certain record and relationship data does not already exist
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1
down vote
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I want to know how to query data from multiple tables with multiple conditions.
My example db has the following tables:
class Location(Base):
__tablename__ = "location"
id = Column('id', Integer, primary_key=True)
location = Column('Location', String)
class Person(Base):
__tablename__ = "person"
id = Column('id', Integer, primary_key=True)
name = Column('Name', String, unique=True)
profession = Column('Profession', String)
location_id = Column(Integer, ForeignKey('location.id'))
location = relationship(Location)
We have in this database a person with a specific location. My goal is to write a query where I can check conditions of the Location table and the Person table.
A person with the name Eric lives in Houston. Now I want to know if I already have an Eric from Houston in my database.
The following query doesn't work.
new_location = Location(location='Houston')
obj = Person(name='Eric', profession='Teacher', location=new_location)
if session.query(Person).filter(Person.name == obj.name,
Person.profession == obj.profession,
Person.location_id == obj.location.id).first() == None:
session.add(obj)
session.commit()
print("Insert sucessful")
The problem in my query is the last line where I check the location but I don't know how to solve it. Maybe someone has a working example with the SQLAlchemy method exists()?
python python-3.x sqlalchemy filtering exists
edited Nov 12 at 15:08
benvc
3,5921319
asked Nov 12 at 10:51
Neal Mc Beal
297
add a comment |
up vote
1
down vote
favorite
I want to know how to query data from multiple tables with multiple conditions.
My example db has the following tables:
class Location(Base):
__tablename__ = "location"
id = Column('id', Integer, primary_key=True)
location = Column('Location', String)
class Person(Base):
__tablename__ = "person"
id = Column('id', Integer, primary_key=True)
name = Column('Name', String, unique=True)
profession = Column('Profession', String)
location_id = Column(Integer, ForeignKey('location.id'))
location = relationship(Location)
We have in this database a person with a specific location. My goal is to write a query where I can check conditions of the Location table and the Person table.
A person with the name Eric lives in Houston. Now I want to know if I already have an Eric from Houston in my database.
The following query doesn't work.
new_location = Location(location='Houston')
obj = Person(name='Eric', profession='Teacher', location=new_location)
if session.query(Person).filter(Person.name == obj.name,
Person.profession == obj.profession,
Person.location_id == obj.location.id).first() == None:
session.add(obj)
session.commit()
print("Insert sucessful")
The problem in my query is the last line where I check the location but I don't know how to solve it. Maybe someone has a working example with the SQLAlchemy method exists()?
python python-3.x sqlalchemy filtering exists
edited Nov 12 at 15:08
benvc
3,5921319
asked Nov 12 at 10:51
Neal Mc Beal
297
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I want to know how to query data from multiple tables with multiple conditions.
My example db has the following tables:
class Location(Base):
__tablename__ = "location"
id = Column('id', Integer, primary_key=True)
location = Column('Location', String)
class Person(Base):
__tablename__ = "person"
id = Column('id', Integer, primary_key=True)
name = Column('Name', String, unique=True)
profession = Column('Profession', String)
location_id = Column(Integer, ForeignKey('location.id'))
location = relationship(Location)
We have in this database a person with a specific location. My goal is to write a query where I can check conditions of the Location table and the Person table.
A person with the name Eric lives in Houston. Now I want to know if I already have an Eric from Houston in my database.
The following query doesn't work.
new_location = Location(location='Houston')
obj = Person(name='Eric', profession='Teacher', location=new_location)
if session.query(Person).filter(Person.name == obj.name,
Person.profession == obj.profession,
Person.location_id == obj.location.id).first() == None:
session.add(obj)
session.commit()
print("Insert sucessful")
The problem in my query is the last line where I check the location but I don't know how to solve it. Maybe someone has a working example with the SQLAlchemy method exists()?
python python-3.x sqlalchemy filtering exists
edited Nov 12 at 15:08
benvc
3,5921319
asked Nov 12 at 10:51
Neal Mc Beal
297
I want to know how to query data from multiple tables with multiple conditions.
My example db has the following tables:
class Location(Base):
__tablename__ = "location"
id = Column('id', Integer, primary_key=True)
location = Column('Location', String)
class Person(Base):
__tablename__ = "person"
id = Column('id', Integer, primary_key=True)
name = Column('Name', String, unique=True)
profession = Column('Profession', String)
location_id = Column(Integer, ForeignKey('location.id'))
location = relationship(Location)
We have in this database a person with a specific location. My goal is to write a query where I can check conditions of the Location table and the Person table.
A person with the name Eric lives in Houston. Now I want to know if I already have an Eric from Houston in my database.
The following query doesn't work.
new_location = Location(location='Houston')
obj = Person(name='Eric', profession='Teacher', location=new_location)
if session.query(Person).filter(Person.name == obj.name,
Person.profession == obj.profession,
Person.location_id == obj.location.id).first() == None:
session.add(obj)
session.commit()
print("Insert sucessful")
The problem in my query is the last line where I check the location but I don't know how to solve it. Maybe someone has a working example with the SQLAlchemy method exists()?
python python-3.x sqlalchemy filtering exists
python python-3.x sqlalchemy filtering exists
edited Nov 12 at 15:08
benvc
3,5921319
asked Nov 12 at 10:51
Neal Mc Beal
297
edited Nov 12 at 15:08
benvc
3,5921319
asked Nov 12 at 10:51
Neal Mc Beal
297
edited Nov 12 at 15:08
benvc
3,5921319
edited Nov 12 at 15:08
benvc
3,5921319
edited Nov 12 at 15:08
benvc
3,5921319
3,5921319
asked Nov 12 at 10:51
Neal Mc Beal
297
asked Nov 12 at 10:51
Neal Mc Beal
297
asked Nov 12 at 10:51
Neal Mc Beal
297
297
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
up vote
1
down vote
accepted
You can do something like the following to join Person and Location and filter for any record where the name and location are the same as the new person instance you have created. The query will either return the record or None, so you can use the result in your if (remember that indentation matters - maybe the code example in your question just copied incorrectly).
new_location = Location(location='Houston')
new_person = Person(name='Eric', profession='Teacher', location=houston)
person_location_exists = session.query(Person).
join(Location).
filter(Person.name == new_person.name).
filter(Location.location == new_location.location).
first()
if person_location_exists:
session.add(new_person)
session.commit()
print("Insert sucessful")
You could use exists() to accomplish the same thing, but I think the above is a bit simpler.
answered Nov 12 at 14:55
benvc
3,5921319
Hey ty for your answer! I found a very similar solution but your solution is much better :)
– Neal Mc Beal
Nov 15 at 10:44
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
accepted
You can do something like the following to join Person and Location and filter for any record where the name and location are the same as the new person instance you have created. The query will either return the record or None, so you can use the result in your if (remember that indentation matters - maybe the code example in your question just copied incorrectly).
new_location = Location(location='Houston')
new_person = Person(name='Eric', profession='Teacher', location=houston)
person_location_exists = session.query(Person).
join(Location).
filter(Person.name == new_person.name).
filter(Location.location == new_location.location).
first()
if person_location_exists:
session.add(new_person)
session.commit()
print("Insert sucessful")
You could use exists() to accomplish the same thing, but I think the above is a bit simpler.
answered Nov 12 at 14:55
benvc
3,5921319
Hey ty for your answer! I found a very similar solution but your solution is much better :)
– Neal Mc Beal
Nov 15 at 10:44
add a comment |
up vote
1
down vote
accepted
You can do something like the following to join Person and Location and filter for any record where the name and location are the same as the new person instance you have created. The query will either return the record or None, so you can use the result in your if (remember that indentation matters - maybe the code example in your question just copied incorrectly).
new_location = Location(location='Houston')
new_person = Person(name='Eric', profession='Teacher', location=houston)
person_location_exists = session.query(Person).
join(Location).
filter(Person.name == new_person.name).
filter(Location.location == new_location.location).
first()
if person_location_exists:
session.add(new_person)
session.commit()
print("Insert sucessful")
You could use exists() to accomplish the same thing, but I think the above is a bit simpler.
answered Nov 12 at 14:55
benvc
3,5921319
Hey ty for your answer! I found a very similar solution but your solution is much better :)
– Neal Mc Beal
Nov 15 at 10:44
add a comment |
up vote
1
down vote
accepted
up vote
1
down vote
accepted
You can do something like the following to join Person and Location and filter for any record where the name and location are the same as the new person instance you have created. The query will either return the record or None, so you can use the result in your if (remember that indentation matters - maybe the code example in your question just copied incorrectly).
new_location = Location(location='Houston')
new_person = Person(name='Eric', profession='Teacher', location=houston)
person_location_exists = session.query(Person).
join(Location).
filter(Person.name == new_person.name).
filter(Location.location == new_location.location).
first()
if person_location_exists:
session.add(new_person)
session.commit()
print("Insert sucessful")
You could use exists() to accomplish the same thing, but I think the above is a bit simpler.
answered Nov 12 at 14:55
benvc
3,5921319
You can do something like the following to join Person and Location and filter for any record where the name and location are the same as the new person instance you have created. The query will either return the record or None, so you can use the result in your if (remember that indentation matters - maybe the code example in your question just copied incorrectly).
new_location = Location(location='Houston')
new_person = Person(name='Eric', profession='Teacher', location=houston)
person_location_exists = session.query(Person).
join(Location).
filter(Person.name == new_person.name).
filter(Location.location == new_location.location).
first()
if person_location_exists:
session.add(new_person)
session.commit()
print("Insert sucessful")
You could use exists() to accomplish the same thing, but I think the above is a bit simpler.
answered Nov 12 at 14:55
benvc
3,5921319
edited Nov 12 at 15:09
answered Nov 12 at 14:55
benvc
3,5921319
answered Nov 12 at 14:55
benvc
3,5921319
answered Nov 12 at 14:55
benvc
3,5921319
3,5921319
Hey ty for your answer! I found a very similar solution but your solution is much better :)
– Neal Mc Beal
Nov 15 at 10:44
add a comment |
Hey ty for your answer! I found a very similar solution but your solution is much better :)
– Neal Mc Beal
Nov 15 at 10:44
Hey ty for your answer! I found a very similar solution but your solution is much better :)
– Neal Mc Beal
Nov 15 at 10:44
Hey ty for your answer! I found a very similar solution but your solution is much better :)
– Neal Mc Beal
Nov 15 at 10:44
add a comment |
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