Question

我在Python中有以下代码，它接受了几个过滤器。然后我有一个循环，在每个上面调用.filter。但是，当您调用多个过滤器时，它们都是AND。如何更改它以便多次调用过滤器进行OR运算。问题出在＆＃34; else＆＃34;我的代码的一部分。

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))

Answer 2

只需在最后建立一个过滤器列表并or_：

exprs = []
for filter_ in filters:
    exprs.append(field.ilike(...))
organizations_products = organizations_products.filter(or_(*exprs))

顺便说一句，实现这样的搜索是一种可靠的性能方式（除非你在PostgreSQL上并且有一个三元组索引，在这种情况下忽略它）。通过使用数据库的全文搜索功能，您可以获得更好的服务。

如何在python中进行多个过滤器调用

2 个答案: