SQLAlchemy的Python数据时间对象问题 [英] Python datatime object issue with SQLAlchemy

问题描述

我正在使用SQLAlchemy，并且遇到SQLite错误的问题：

I am using SQLAlchemy and am having an issue wrt to an SQLite error:

SQLite Date type only accepts Python date objects as input. 
[SQL: 'SELECT anon_1.patient_sid AS sid FROM 
(SELECT clinical_data.patient_sid AS patient_sid FROM clinical_data 
WHERE clinical_data.event_date >= ?) AS anon_1']

我完全理解错误的含义，但是我不明白为什么我会遇到这种错误。

I understand perfectly the meaning of the error, but I do not understand why it is happening in my case.

我在 clinical_data.event_date> =？上面的查询中传递的用于进行日期比较的参数设置为：

The parameter that I am passing to do the date comparison in the query above clinical_data.event_date >= ?, is set as:

valdate = datetime.strptime('1776-01-01 00:00:00', "%Y-%m-%d %H:%M:%S").date()

验证 valdate 的数据类型为< type'datetime.date'>

用于构造查询的类为：

class ClinicalData(db.Model):
    __tablename__ = 'clinical_data'
    id = Column(Integer, primary_key=True, autoincrement=True)
    patient_id = Column(Integer)
    patient_sid  = Column(Integer)
    string_value = Column(String(255))
    double_value = Column(Float)
    data_type_id = Column(Integer)
    event_date = Column(Date)
    ontology_id = Column(Integer)
    attribute_id = Column(Integer)
    project_id = Column(Integer)
    replaced_by_id = Column(Integer)
    date_record_added = Column(DateTime)
    parent = Column(Integer)
    num_children = Column(Integer)
    lft = Column(Integer)
    rgt = Column(Integer)

SQLite状态的SQLAlchemy文档（请参见 SQLAlchemy SQLite文档），当使用SQlite时，SQLAlchemy自己的DateTime和相关类型提供了日期格式和解析功能……

The SQLAlchemy documentation for SQLite states (see SQLAlchemy SQLite documentation) that "SQLAlchemy’s own DateTime and related types provide date formatting and parsing functionality when SQlite is used..."

我既不问如何将我的字符串对象转换为python datetime对象，也不问该错误意味着什么。我不确定到底为什么当所有东西都定义得足够好时，我仍然不断收到此错误。

I am not asking how to convert my string object to a python datetime object, nor am I asking what the error means. I am not sure exactly why I keep getting this error when everything appears to be sufficiently defined.

EDIT

EDIT

请注意，当我在 event_date DateTime 时c>属性，出现以下错误 SQLite DateTime类型仅接受Python datetime和date对象作为输入。为此，我定义了 valdate = datetime.strptime（ '1776-01-01 00:00:00'，％Y-％m-％d％H：％M：％S）而没有 date（） 方法。如预期的那样，在这种情况下， type（valdate）产生< type'datetime.datetime'> 。

Note that when I use DateTime in my model on the event_date attribute I get the following error SQLite DateTime type only accepts Python datetime and date objects as input. For this I define valdate = datetime.strptime('1776-01-01 00:00:00', "%Y-%m-%d %H:%M:%S") without the date() method. As expected, type(valdate) in this case yields <type 'datetime.datetime'>.

我尝试了将变量 valdate 与 event_date 我班的属性。

I have tried every combination of creating the variable valdate with the event_date attribute of my class.

推荐答案

错误提示：

SQLite Date类型仅接受Python日期对象作为输入。

SQLite Date type only accepts Python date objects as input.

但是您没有 date 对象-您有一个 datetime 对象！要将您的日期时间转换为日期，只需调用其 date（） 方法-尽管根据事实判断您的 strptime 格式包含时间字段（％H：％M：％S ），您可能需要更改 event_date 从 Column（Date）到 Column（DateTime）

But you don't have a date object — you have a datetime object! To turn your datetime into a date, just call its date() method — though judging by the fact that your strptime format includes time fields (%H:%M:%S), you might want to change event_date from Column(Date) to Column(DateTime) instead.

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