SQLAlchemy insert values into reflected table 结果全部为 NULL 条目

Question

以下代码每次尝试都会导致 None () 跨行。下面的 query.values() 代码只是一个缩短的行，以使事情不那么复杂。此外，我在地址字段中插入字典作为 JSON 时遇到问题，但这是另一个问题。

CREATE TABLE public.customers (
    id SERIAL,
    email character varying(255)  NULL,
    name character varying(255)  NULL,
    phone character varying(16)  NULL,
    address jsonb  NULL,
    shipping jsonb  NULL,
    currency character varying(3)  NULL,
    metadata jsonb[]  NULL,
    created bigint  NULL,
    uuid uuid DEFAULT uuid_generate_v4() NOT NULL,
    PRIMARY KEY (uuid)
);

from sqlalchemy import *
from sqlalchemy.orm import Session

# Create engine, metadata, & session
engine = create_engine('postgresql://postgres:password@database/db', future=True)
metadata = MetaData(bind=engine)
session = Session(engine)

# Create Table
customers = Table('customers', metadata, autoload_with=engine)

query = customers.insert()
query.values(email="test@test.com", \
             name="testy testarosa", \
             phone="+12125551212", \
             address='{"city": "Cities", "street": "123 Main St", \
                        "state": "CA", "zip": "10001"}')


session.execute(query)
session.commit()
session.close()

# Now to see results
stmt = text("SELECT * FROM customers")
response = session.execute(stmt)

for result in response:
    print(result)

# Results in None in the fields I explicitly attempted 
(1, None, None, None, None, None, None, None, 1, None, None, None, None, UUID('9112a420-aa36-4498-bb56-d4129682681c'))

Answer 1

我不知道你说的是什么意思

The query.values() code below is just a shortened line so as to keep things less complicated.

所以我可能没有正确理解这个问题。无论如何，这里的问题是您分别执行 insert() 和 values()，而它本来是要“链接”的。

做类似的事情：

query = customers.insert().values(email="test@test.com", name="testy testarosa", phone="+12125551212", address='{"city": "Cities", "street": "123 Main St", "state": "CA", "zip": "10001"}')

会起作用。

文档：https://docs.sqlalchemy.org/en/14/core/selectable.html#sqlalchemy.sql.expression.TableClause.insert

PS：我也没有遇到 JSON 字段的任何问题。也许是 PG 版本的东西？

Answer 2

调用 query.values() return 一个新的 insert 实例，而不是就地修改现有实例。此 return 值必须分配给变量，否则它将无效。

您可以迭代构建插入

query = customers.insert()
query = query.values(...)
session.execute(query)

或链调用为Karolus K. suggests in their 。

query = customers.insert().values(...)

关于 address 列，您正在插入一个已经序列化为 JSON 的字典。该值在插入期间再次序列化，因此数据库中的值最终如下所示：

test# select address from customers;
                                                       address                                                        
══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════
 "{\"city\": \"Cities\", \"street\": \"123 Main St\",                         \"state\": \"CA\", \"zip\": \"10001\"}"
(1 row)

并且不适合作为 JSON 对象进行查询（因为它是 JSON 化的 字符串 ）

test# select address->'state' AS state from customers;
 state 
═══════
 ¤
(1 row)

您可能会发现传递原始字典会更好，从而将此值存储在数据库中：

test# select address from customers;
                                  address                                   
════════════════════════════════════════════════════════════════════════════
 {"zip": "10001", "city": "Cities", "state": "CA", "street": "123 Main St"}
(1 row)

可以作为 JSON 对象查询：

test# select address->'state' AS state from customers;
 state 
═══════
 "CA"
(1 row)

SQLAlchemy insert values into reflected table 结果全部为 NULL 条目

SQLAlchemy insert values into reflected table results in NULL entries all across

python

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postgresql

sqlalchemy