python - 反射(reflect) SQL Server 表时删除排序规则表达式

Question

我正在尝试使用 Python SQLAlchemy 将 MS SQL Server View 反射(reflect)到 SQLite 表中。

问题是 sqlalchemy 将 COLLATE "SQL_Latin1_General_CP1_CI_AS"添加到各种 NVARCHAR 列，这在 sqlite 中不受支持。

是否有一种与列名无关的方法从表定义中删除所有 COLLATES？

from sqlalchemy import *
from sqlalchemy.orm import create_session
from sqlalchemy.ext.declarative import declarative_base
import urllib
from sqlalchemy.orm import sessionmaker

#Create and engine and get the metadata
Base = declarative_base()
source_connection = 'msql+pyodbc...'
source_engine = create_engine(source_connection)
metadata = MetaData(bind=source_engine)
SourceSession = sessionmaker(source_engine)

#destination
dest_engine = create_engine('sqlite:///...', echo=True)
DestSession = sessionmaker(dest_engine)


#Reflect each database table we need to use, using metadata
class tblR(Base):
    __table__ = Table('tblR', metadata, 
                      Column("r_id", Integer, primary_key=True),
                      autoload=True)


#Create a session to use the tables    


# This is the query we want to persist in a new table:
sourceSession = SourceSession()
query= sourceSession.query(tblR.r_id, tblR.MK_Assumed).filter_by(r_id=0)


# Build the schema for the new table
# based on the columns that will be returned 
# by the query:
metadata = MetaData(bind=dest_engine)
columns = [Column(desc['name'], desc['type']) for desc in query.column_descriptions]
column_names = [desc['name'] for desc in query.column_descriptions]
table = Table("newtable", metadata, *columns)


# Create the new table in the destination database
table.create(dest_engine)

# Finally execute the query
destSession = DestSession()
for row in query:
    destSession.execute(table.insert(row))
destSession.commit()

我收到以下错误:

sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such collation sequence: SQL_Latin1_General_CP1_CI_AS [SQL: '\nCREATE TABLE newtable (\n\tr_id INTEGER, \n\t"MK_Assumed" NVARCHAR(20) COLLATE "SQL_Latin1_General_CP1_CI_AS"\n)\n\n'] (Background on this error at: http://sqlalche.me/e/e3q8)

Answer 1

我遇到了类似的问题，我是这样解决的:

for table in metadata.sorted_tables :
    for col in table.c:
        if getattr(col.type, 'collation', None) is not None:
            col.type.collation = None

编辑:为了更明确的控制，您似乎可以指定'BINARY'、'NOCASE' 或'RTRIM '

sqlite.org > datatypes > collations