python - 如何在 python 中对多个过滤器调用进行 OR 运算

Question

我有以下 Python 代码，它接受多个过滤器。然后我有一个循环对每个对象调用 .filter 。但是，当您调用多个过滤器时，这些过滤器将进行“与”运算。我怎样才能改变它，以便对过滤器的多个调用进行“或”运算。问题出在我的代码的“else”部分。

for filter_ in filters:
        field_models = {'type': ProductType, 'category': ProductCategory}
        if filter_['field'] in field_models:
            model = field_models[filter_['field']]
            organizations_products = organizations_products.join(model).filter(or_(
                model.code.ilike('%{}%'.format(escape_like(filter_['value']))),
                model.description.ilike('%{}%'.format(escape_like(filter_['value'])))
            ))
        else:
            field = getattr(Product, filter_['field'])
            organizations_products = organizations_products.filter(
                field.ilike('%{}%'.format(escape_like(filter_['value']))))

Answer 1

解决方案分为两部分。首先，我们必须构造 from 子句，然后构造 where 子句。

def get_joined_stmt(filters, stmt):
    if 'type' in filters.keys():
        stmt = stmt.join(ProductType)
    if 'category' in filters.keys():
        stmt = stmt.join(ProductCategory)
    return stmt

def get_exprs(field, value):
    def _ilike_expr(x): return '%{}%'.format(escape_like(x))

    model_dict = {'type': ProductType, 'category': ProductCategory}
    model = model_dict[field]
    stmt = organizations_products.join(model)
    try: 
        return [model.code.ilike(_ilike_expr(value)),
                model.description.ilike(_ilike_expr(value))]
    except KeyError:
        return [getattr(Product, field).ilike(_ilike_expr(value))]

organizations_products = get_joined_stmt(filters, organizations_products)

where_exprs = []
for filter_ in filters.items():
    where_exprs.extend(get_exprs(**filter_))

organizations_products = organizations_products.filter(or_(*where_exprs))