如何将不同的参数传递给使用各自的sqlalchemy orm类更新不同表的函数？

Question

使用sqlalchemy orm，对于数据库中的不同表，我具有不同的类。例如，以下是其中两个：

class PortfolioDim(SqlAlchemyBase):
    __tablename__ = 'portfoliodim'

    Id = sa.Column(sa.Integer, primary_key=True, autoincrement=True)
    PortfolioId = sa.Column(sa.String, index=True)
    CompositeFrenchName = sa.Column(sa.String, index=True)
    StartDate = sa.Column(sa.DateTime)
    EndDate = sa.Column(sa.DateTime)
    Benchmark = sa.Column(sa.String)
    ClientOrFundName = sa.Column(sa.String) 
    LastUpdated = sa.Column(sa.DateTime, default=datetime.datetime.now)


class ValueFact(SqlAlchemyBase):
    __tablename__ = 'valuefact'

    Id = sa.Column(sa.Integer, primary_key=True, autoincrement=True)
    PortfolioId = sa.Column(sa.String, index=True)
    Date = sa.Column(sa.DateTime, index=True)
    Currency = sa.Column(sa.String, index=True)
    OpeningValue = sa.Column(sa.Float)
    ClosingValue = sa.Column(sa.Float)
    CashFlow = sa.Column(sa.Float)

    LastUpdated = sa.Column(sa.DateTime, default=datetime.datetime.now, index=True)

到目前为止，我编写了2个不同的函数来更新每个函数。分别：

def update_valuefact(connecstr, dropindic, filedata):
   ''' Update value fact table, where filedata 
        is a list of rows, using sqlalchemy orm 

   '''

    dbsession.init_db(connecstr, dropindic, 
        tableclassunderfocus=ValueFact)

    session = dbsession.create_session()

    for row in filedata:  
        valeur = ValueFact(CashFlow=row[0],
        ClosingValue= row[1],
        Currency= row[2],
        Date = row[3],
        OpeningValue= row[4],
        PortfolioId = row[5]
        )

        session.add(valeur)

    session.commit()



def update_portfoliodim(connecstr, dropindic, filedata):
    ''' Update portfolio dimension table, 
    where filedata is a list of rows, using sqlalchemy orm 

    '''

    dbsession.init_db(connecstr, dropindic, 
           tableclassunderfocus=PortfolioDim)

    session = dbsession.create_session()

    for row in filedata:  

        portefeuille = PortfolioDim(Benchmark= row[0],
        ClientOrFundName = row[1],
        CompositeFrenchName=row[2],
        EndDate = row[3],
        PortfolioId= row[4],
        StartDate= row[5]
        )

        session.add(portefeuille)

    session.commit()

假设数据库正在扩展，我想编写一个update_table函数。我当时想我可以给它传递一个字典，该字典列出各个表中的各个字段，例如：

tablefieldsdicos = {'portfoliodim': {'PortfolioId': 'str', 'CompositeFrenchName': 'str',
                            'StartDate': 'datetime', 'EndDate': 'datetime', 'ClientOrFundName': 'str',
                            'Benchmark': 'str'},
                    'valuefact': {'CashFlow': 'float', 'Currency': 'str', 
                            'ClosingValue': 'float',
                            'Date': 'datetime', 'OpeningValue': 'float', 'PortfolioId': 'str'}}

def update_table(connecstr, dropindic, filedata, tableclassunderfocus,
                tablefieldsdico):

    ''' update a single table
    filedata: list of rows (loaded from a csv file)
    tableclassunderfocus: class matching table in sa orm
    tablefieldsdico: dictionary where the keys are the name of the fields in alphabetical order
    (order matching the order of the columns in source file "filedata")

    '''

    dbsession.init_db(connecstr, dropindic, tableclassunderfocus)

    session = dbsession.create_session()

    colindices = []
    fields = []

    for k, field in enumerate(tablefieldsdico.keys()):
        colindices.append(k)
        fields.append(field)

    for row in filedata:  
        portefeuille = tableclassunderfocus(Benchmark= row[0],
        ClientOrFundName = row[1],
        CompositeFrenchName=row[2],
        EndDate = row[3],
        PortfolioId= row[4],
        StartDate= row[5]
        )

        session.add(portefeuille)

    session.commit()

我想知道如何将列表字段和colindices作为参数传递给tableunderfocus所指向的类。字段中的项目应在此处替换Benchmark，ClientOrFundName，...，StartDate，但是对于不同的类/表，字段将有所不同（字段列表的长度将有所不同）。 colindices中的项目应替换行[*]中的索引。

有解决此问题的建议吗？包括编写这种功能的完全不同的方法吗？

Answer 1

首先，创建一个字典列表，其中键是表字段，值是数据源文件中一行的元素。然后将字典列表传递给sqlalchemy bulk_insert_mappings函数，如Ilja的注释所指出的。

def update_table(connecstr, dropindic, filedata, tableclassunderfocus, tablename):
    ''' update a single table
    filedata: list of dictionaries
     (1 dictionary: keys are table fields; values are elements in source data rows (e.g. loaded from a csv file))
    tableclassunderfocus: class matching table in sa orm
    tablename: name of table in db    
    '''

    dbsession.init_db(True, connecstr, dropindic, tableclassunderfocus)

    session = dbsession.create_session()

    session.bulk_insert_mappings(tableclassunderfocus, filedata)

    session.commit()