python SQLAlchemy 插入忽略
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SQLAlchemy INSERT IGNORE
提问by spacemonkey
How can I insert multiple data records into table ignoring duplicates. I am using SQLAlchemy.
如何将多个数据记录插入表中而忽略重复项。我正在使用 SQLAlchemy。
Thank you!
谢谢！
回答by joeforker
prefix_with("TEXT")adds arbitrary text between INSERTand the rest of the SQL. execute()accepts a list of dictionaries with the records you would like to insert or a single dictionary if you only want to insert a single record.
prefix_with("TEXT")INSERT在 SQL 的其余部分之间添加任意文本。execute()接受包含您要插入的记录的字典列表，或者如果您只想插入单个记录，则接受单个字典。
The SQLite syntax for the behavior you're looking for:
您正在寻找的行为的 SQLite 语法：
inserter = table_object.insert().prefix_with("OR REPLACE")
inserter.execute([{'column1':'value1'}, {'column1':'value2'}])
回答by Thomas
To always replace INSERTby INSERT OR IGNORE, you can use a compiler extension:
要始终替换INSERT为INSERT OR IGNORE，您可以使用编译器扩展：
from sqlalchemy.ext.compiler import compiles
from sqlalchemy.sql.expression import Insert
@compiles(Insert)
def _prefix_insert_with_ignore(insert, compiler, **kw):
return compiler.visit_insert(insert.prefix_with('OR IGNORE'), **kw)
Or to do this only temporarily, call the compilesdecorator manually and use deregisteronce you're done:
或者只是暂时执行此操作，请compiles手动调用装饰器并deregister在完成后使用：
from sqlalchemy.ext.compiler import compiles, deregister
from sqlalchemy.sql.expression import Insert
def _prefix_insert_with_ignore(insert, compiler, **kw):
return compiler.visit_insert(insert.prefix_with('OR IGNORE'), **kw)
compiles(Insert)(_prefix_insert_with_replace)
try:
# do some inserts...
finally:
deregister(Insert)
This does feel hacky because it's still a global change, but as long as you don't use threads and make sure everything is properly committed before the deregistercall, it's probably okay.
这确实让人感觉很棘手，因为它仍然是一个全局更改，但是只要您不使用线程并确保在deregister调用之前正确提交所有内容，就可能没问题。
