来自筛选器长度的不兼容比较错误

Question

问题

下面详细介绍了一个不兼容的比较错误，但它取决于传递给过滤器的字符串的大小。有人知道这个错误的原因或解决方法是什么，或者我可以在哪里深入挖掘以确定根本问题吗？你知道吗

详细信息

当我使用长度为255的字符串查询筛选时，我会收到一个False响应（与插入的列值不完全匹配）：

>>> from core.models import TestTable
>>> test_str = '--publication_filter|920,921,922,923,925,926,927,928,929,930,932,933,934,935,936,937,938,939,940,941,1024,1237,1239,1255,1302,1386,1442,1724,1842,9926,9929,9979,12818,12822,12864,12867,21301,21417,21418,21419,21420,21570,22046,22080,22081,22087,22167,1234'
>>> len(test_str)
255
>>> test1 = TestTable.objects.filter(test_column=test_str)
>>> test1.exists()
False

但是，对于长度为256的字符串，我希望返回True（与插入的列值匹配），它反而会引发错误（此测试与上面的测试完全相同，只是test_str长一个字符）：

注意：我在下面的回溯中编辑了我的路径。你知道吗

>>> from core.models import TestTable
>>> test_str = '--publication_filter|920,921,922,923,925,926,927,928,929,930,932,933,934,935,936,937,938,939,940,941,1024,1237,1239,1255,1302,1386,1442,1724,1842,9926,9929,9979,12818,12822,12864,12867,21301,21417,21418,21419,21420,21570,22046,22080,22081,22087,22167,12345'
>>> len(test_str)
256
>>> test2 = TestTable.objects.filter(test_column=test_str)
>>> test2.exists()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/[REDACTED]/.venv/local/lib/python2.7/site-packages/django/db/models/query.py", line 565, in exists
    return self.query.has_results(using=self.db)
  File "/[REDACTED]/.venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py", line 441, in has_results
    return bool(compiler.execute_sql(SINGLE))
  File "/[REDACTED]/.venv/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 818, in execute_sql
    cursor.execute(sql, params)
  File "/[REDACTED]/.venv/local/lib/python2.7/site-packages/sql_server/pyodbc/base.py", line 325, in execute
    return self.cursor.execute(sql, params)
ProgrammingError: ('42000', '[42000] [FreeTDS][SQL Server]The data types nvarchar and text are incompatible in the equal to operator. (402) (SQLParamData)')

查看并运行原始查询效果很好，这让我对所使用的django-pyodbc包非常怀疑。你知道吗

>>> str(TestTable.objects.filter(test_column=test_str).query)
'SELECT [custom].[test_table].[test_id], [custom].[test_table].[test_column] FROM [custom].[test_table] WHERE [custom].[test_table].[test_column] = --publication_filter|920,921,922,923,925,926,927,928,929,930,932,933,934,935,936,937,938,939,940,941,1024,1237,1239,1255,1302,1386,1442,1724,1842,9926,9929,9979,12818,12822,12864,12867,21301,21417,21418,21419,21420,21570,22046,22080,22081,22087,22167,12345 '

已编辑的查询（引号已修复），手动查询my DB时无问题返回：

SELECT [custom].[test_table].[test_id], [custom].[test_table].[test_column]
FROM [custom].[test_table]
WHERE [custom].[test_table].[test_column] = '--publication_filter|920,921,922,923,925,926,927,928,929,930,932,933,934,935,936,937,938,939,940,941,1024,1237,1239,1255,1302,1386,1442,1724,1842,9926,9929,9979,12818,12822,12864,12867,21301,21417,21418,21419,21420,21570,22046,22080,22081,22087,22167,12345'

附加信息

系统

• 服务器操作系统：Ubuntu 14.04.5 LTS
• DB驱动程序：FreeTDS
• djanbo-pyodbc包：https://github.com/avidal/django-pyodbc/tree/django-1.4
  • 注意：出于某种未知的原因，我们基于此包的本地存储副本构建了我们的项目，但我相信这是该包的分支。你知道吗

表

CREATE TABLE [custom].[test_table] (
    test_id INT NOT NULL PRIMARY KEY IDENTITY(1, 1),
    test_column NVARCHAR(4000),
);

INSERT INTO custom.test_table (test_column)
VALUES ('--publication_filter|920,921,922,923,925,926,927,928,929,930,932,933,934,935,936,937,938,939,940,941,1024,1237,1239,1255,1302,1386,1442,1724,1842,9926,9929,9979,12818,12822,12864,12867,21301,21417,21418,21419,21420,21570,22046,22080,22081,22087,22167,12345');

型号

class TestTable(models.Model):
    test_id = models.AutoField(primary_key=True)
    test_column = models.TextField(null=True)
    class Meta:
        db_table = u'custom].[test_table'

Answer 1

有几种django-pyodbc风格，但在我尝试过的包中，django-pyodbc-azure表现最好。我建议尝试一下：

https://github.com/michiya/django-pyodbc-azure