SQLAlchemy update if unique key exists

Question

I\'ve got a class:

class Tag(Base, TimestampMixin):
    \"\"\"Tags\"\"\"
    __tablename__ = \'tags\'
    __table_args__ = {\'mysql_engine\' : \'InnoDB\', \'         


        

Answer 1

From version 1.2 SQLAlchemy will support on_duplicate_key_update for MySQL

There is also examples of how to use it:

from sqlalchemy.dialects.mysql import insert

insert_stmt = insert(my_table).values(
    id='some_existing_id',
    data='inserted value')

on_duplicate_key_stmt = insert_stmt.on_duplicate_key_update(
    data=insert_stmt.values.data,
    status='U'
)

conn.execute(on_duplicate_key_stmt)

---

From version 1.1 SQLAlchemy support on_conflict_do_update for PostgreSQL

Examples:

from sqlalchemy.dialects.postgresql import insert

insert_stmt = insert(my_table).values(
    id='some_existing_id',
    data='inserted value')

do_update_stmt = insert_stmt.on_conflict_do_update(
    constraint='pk_my_table',
    set_=dict(data='updated value')
)

conn.execute(do_update_stmt)

Answer 2

You can try this

def get_or_increase_tag(tag_name):
    tag = session.query(Tag).filter_by(tag=tag_name).first()
    if not tag:
       tag = Tag(tag_name)
    else:
       tag.cnt += 1
    return tag

You can check the link https://stackoverflow.com/search?q=Insert+on+duplicate+update+sqlalchemy