遵循此question:
正如IljaEveilä在他的answer中提到的,我创建了一个表对象:
from sqlalchemy import *
metadata = MetaData()
idTagTable = Table('id_tag', metadata,
Column('id', String(255), primary_key = True),
Column('category', String(20), nullable = False),
Column('createddate', Date, nullable = False),
Column('updatedon', Date, nullable = False)
)
创建表对象后,我更改了insert和update语句:
insert_statement = sqlalchemy.dialects.postgresql.insert(idTagTable)
upsert_statement = insert_statement.on_conflict_do_update(
constraint=PrimaryKeyConstraint('id'),
set_={"updatedon": insert_statement.excluded.updateon,
"category":insert_statement.excluded.category}
)
insert_values = df.to_dict(orient='records')
conn.execute(upsert_statement, insert_values)
现在我收到编程错误:
Traceback (most recent call last):
File "<ipython-input-66-0fc6a1bf9c6b>", line 7, in <module>
conn.execute(upsert_statement, insert_values)
File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 945, in execute
return meth(self, multiparams, params)
File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/sqlalchemy/sql/elements.py", line 263, in _execute_on_connection
return connection._execute_clauseelement(self, multiparams, params)
File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1053, in _execute_clauseelement
compiled_sql, distilled_params
File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1189, in _execute_context
context)
File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1402, in _handle_dbapi_exception
exc_info
File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/sqlalchemy/util/compat.py", line 203, in raise_from_cause
reraise(type(exception), exception, tb=exc_tb, cause=cause)
File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1159, in _execute_context
context)
File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/sqlalchemy/engine/default.py", line 467, in do_executemany
cursor.executemany(statement, parameters)
ProgrammingError: (psycopg2.ProgrammingError) syntax error at or near
")"
LINE 1: ...category) VALUES ('sports') ON CONFLICT () DO UPDAT...
^
无法理解我收到此错误的原因。
答案 0 :(得分:1)
您作为PrimaryKeyConstraint
参数使用的constraint=
对象未绑定到任何表格,并且在呈现时似乎不会产生任何内容,如ON CONFLICT ()
中所示。而是将表的主键作为 conflict_target 传递,Postgresql将执行唯一的索引推理:
upsert_statement = insert_statement.on_conflict_do_update(
constraint=idTagTable.primary_key,
set_={"updatedon": insert_statement.excluded.updateon,
"category":insert_statement.excluded.category}
)