Postgresql Sqlalchemy dynamic table partition creation issue

Question

I'm using postgresql and python sqllachmey for creating the partitioned table. Below is the example code.

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.types import Text
Base = declarative_base()
class Students(Base):
    __tablename__ = "Students"

    id = Column(Text, primary_key=True)
    name = Column(Text)
    type = Column(Text)
    desc = Column(Text)
    creation_time = Column(DateTime, default=func.now(), nullable=False, primary_key=True)
    __table_args__ = {
        'postgresql_partition_by': 'RANGE (creation_time)'
    }
table_list = [Students.__table__]
Base.metadata.create_all(self.engine, tables=table_list)

The above code creates a paritioned table and i'm creating the partitions using pg_partman extension.

Now, my need is that I want to use the class 'Students' for creating the student table under different databases, and some databases don't need the partitioned table. How can I make the above code dynamic so that I can take out 'postgresql_partition_by' from table_args?

According to the documents, it looks like, I have to use dictionary for table column definition but I'm not quite sure about it.

Answer 1

The keyword arguemnts of Table (or __table_args__) are dialect specific, so your postgresql_partition_by will only be used with postgresql dialects, not sqlite or others.

class sqlalchemy.schema.Table(*args, **kw)

[...]

**kw – Additional keyword arguments not mentioned above are dialect specific, and passed in the form <dialectname>_<argname>. See the documentation regarding an individual dialect at Dialects for detail on documented arguments.