问题：
将数据框导入SQL表时，出现截断错误：
sqlalchemy.exc.DataError: (pyodbc.DataError) ('22001', '[22001] [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]String or binary data would be truncated. (8152) (SQLExecDirectW); [22001] [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]The statement has been terminated. (3621)')
有问题的列是 ProjectDescription （请参见下面的列列表）。我已引用产生错误的行。我不完全确定这是问题的根源，但我认为该列最初创建为VARCHAR（300）。引起麻烦的值是307个字符长； 9被截断如下。剩下298。原来的大小限制为300，为2表示，我想剩下298？不确定，但是要截短是一个奇怪的长度。
导致问题的代码：
dataframe.to_sql('tblImport', eng, schema='dbo', if_exists='append', index=False, dtype=dict_SQL_dtypes)
尝试的解决方案：
sqlalchemy.types.VARCHAR（来自here的想法）版本：
数据库连接：
pyodbc.connect("DRIVER={{ODBC Driver 13 for SQL Server}};SERVER={0};DATABASE={1};UID={2};PWD={3}".format(serv, db, usr, pwd))
引擎：
create_engine('mssql+pyodbc://{}@sqlserver:{}@{}:1433/{}?driver=ODBC+Driver+13+for+SQL+Server'.format(usr, pwd, serv, db), echo=True)
数据库架构中的ProjectDescription列character_maximum_length：-1
列：
Column Name | Data Type | Allow Nulls
ProjectUID | varchar(60) | Unchecked
Framework | char(5) | Checked
Partner | char(3) | Checked
SCUID | char(9) | Checked
ClientName | varchar(255) | Checked
PartnerProjectNumber | varchar(40) | Checked
ProjectName | varchar(255) | Checked
ProjectDescription | varchar(MAX) | Checked
跟踪：
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\engine\base.py", line 1216, in _execute_context
cursor, statement, parameters, context
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\engine\default.py", line 533, in do_executemany
cursor.executemany(statement, parameters)
pyodbc.DataError: ('22001', '[22001] [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]String or binary data would be truncated. (8152) (SQLExecDirectW); [22001] [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]The statement has been terminated. (3621)')
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "run_for_tests.py", line 258, in <module>
outmsg = run()
File "run_for_tests.py", line 252, in run
process_result = process_data(file_type, file_name, relative_path, dict_clients)
File "run_for_tests.py", line 204, in process_data
update_sql_tables(df_base)
File "server_interaction.py", line 74, in update_sql_tables
dataframe.to_sql('tblImport', eng, schema='dbo', if_exists='append', index=False, dtype=dict_SQL_dtypes)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\pandas\core\generic.py", line 2532, in to_sql
dtype=dtype, method=method)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\pandas\io\sql.py", line 460, in to_sql
chunksize=chunksize, dtype=dtype, method=method)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\pandas\io\sql.py", line 1174, in to_sql
table.insert(chunksize, method=method)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\pandas\io\sql.py", line 686, in insert
exec_insert(conn, keys, chunk_iter)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\pandas\io\sql.py", line 599, in _execute_insert
conn.execute(self.table.insert(), data)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\engine\base.py", line 980, in execute
return meth(self, multiparams, params)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\sql\elements.py", line 273, in _execute_on_connection
return connection._execute_clauseelement(self, multiparams, params)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\engine\base.py", line 1099, in _execute_clauseelement
distilled_params,
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\engine\base.py", line 1240, in _execute_context
e, statement, parameters, cursor, context
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\engine\base.py", line 1458, in _handle_dbapi_exception
util.raise_from_cause(sqlalchemy_exception, exc_info)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\util\compat.py", line 296, in raise_from_cause
reraise(type(exception), exception, tb=exc_tb, cause=cause)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\util\compat.py", line 276, in reraise
raise value.with_traceback(tb)
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\engine\base.py", line 1216, in _execute_context
cursor, statement, parameters, context
File "AppData\Local\Programs\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\sqlalchemy\engine\default.py", line 533, in do_executemany
cursor.executemany(statement, parameters)
sqlalchemy.exc.DataError: (pyodbc.DataError) ('22001', '[22001] [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]String or binary data would be truncated. (8152) (SQLExecDirectW); [22001] [Microsoft][ODBC Driver 13 for SQL Server][SQL Server]The statement has been terminated. (3621)') [SQL: 'INSERT INTO dbo.[tblImport] ([ProjectUID], [Framework], [Partner], [SCUID], [ClientName], [PartnerProjectNumber], [ProjectName], [ProjectDescription]) VALUES (?, ?, ?, ?, ?, ?, ?, ?)'] [parameters: (('xxx', 'xxxxx', 'xxx', 'xxxxxxx', 'ABC', 123, 'ABC', 'Provide competition facilities. Build this facility with a capacity of 9000 spectators ... (9 characters truncated) ... m pool and diving facilities and athletes changing facilities to a competion standard and then, post games, convert it to a council operated facility'), ....)] (Background on this error at: http://sqlalche.me/e/9h9h)