SQLAlchemy PostgreSQL UPSERT数组值

Question

尝试对PostgreSQL> 9.5的值数组执行UPSERT。

试图构建SQLALchemy文档中的语句，但没有解释如何为数组而不是单行执行此操作。 insert语句的构建正确，所以我想可以使用on_conflict_do_update函数来完成。

有了这个代码：

stock_table = Table("stock_history", metadata, 
      Column('date', sqlalchemy.types.NVARCHAR(length=255), primary_key=True), 
      Column('product_id', sqlalchemy.types.INTEGER(), primary_key=True), 
      Column('product_sku', sqlalchemy.types.NVARCHAR(length=255)), 
      Column('on_hand_qty', sqlalchemy.dialects.postgresql.DOUBLE_PRECISION()), 
      Column('available_qty', sqlalchemy.dialects.postgresql.DOUBLE_PRECISION()), 
      Column('output_qty', sqlalchemy.dialects.postgresql.DOUBLE_PRECISION()) 
     ) 
stock_today = pandas.read_sql_query(queryStock, odoo_engine) 
insert_stmt = sqlalchemy.dialects.postgresql.insert(stock_table).values(stock_today) 
upser_stmt = insert_stmt.on_conflict_do_update(
      index_elements=['date', 'product_id'], 
      set_=stock_today.to_dict(orient='dict') 
     ) 

，我发现了以下错误：

AttributeError的： 'StrSQLCompiler' 对象有没有属性 'visit_on_conflict_do_update'

During handling of the above exception, another exception occurred: 

    Traceback (most recent call last): 
     File "pompeiiETL.py", line 15, in <module> 
     pompeiiJobs.runStockJob(dwh_engine, odoo_prod_engine) 
     File "/Users/alex/Development/DataLab/pompeii-datalab/pompeiiETL/jobs.py", line 54, in runStockJob 
     print(upser_stmt) 
     File "/Users/alex/Development/DataLab/ETLenv/lib/python3.6/site-packages/sqlalchemy/sql/elements.py", line 446, in __str__ 
     return str(self.compile()) 
     File "<string>", line 1, in <lambda> 
     File "/Users/alex/Development/DataLab/ETLenv/lib/python3.6/site-packages/sqlalchemy/sql/elements.py", line 436, in compile 
     return self._compiler(dialect, bind=bind, **kw) 
     File "/Users/alex/Development/DataLab/ETLenv/lib/python3.6/site-packages/sqlalchemy/sql/elements.py", line 442, in _compiler 
     return dialect.statement_compiler(dialect, self, **kw) 
     File "/Users/alex/Development/DataLab/ETLenv/lib/python3.6/site-packages/sqlalchemy/sql/compiler.py", line 435, in __init__ 
     Compiled.__init__(self, dialect, statement, **kwargs) 
     File "/Users/alex/Development/DataLab/ETLenv/lib/python3.6/site-packages/sqlalchemy/sql/compiler.py", line 216, in __init__ 
     self.string = self.process(self.statement, **compile_kwargs) 
     File "/Users/alex/Development/DataLab/ETLenv/lib/python3.6/site-packages/sqlalchemy/sql/compiler.py", line 242, in process 
     return obj._compiler_dispatch(self, **kwargs) 
     File "/Users/alex/Development/DataLab/ETLenv/lib/python3.6/site-packages/sqlalchemy/sql/visitors.py", line 81, in _compiler_dispatch 
     return meth(self, **kw) 
     File "/Users/alex/Development/DataLab/ETLenv/lib/python3.6/site-packages/sqlalchemy/sql/compiler.py", line 2041, in visit_insert 
     insert_stmt._post_values_clause, **kw) 
     File "/Users/alex/Development/DataLab/ETLenv/lib/python3.6/site-packages/sqlalchemy/sql/compiler.py", line 242, in process 
     return obj._compiler_dispatch(self, **kwargs) 
     File "/Users/alex/Development/DataLab/ETLenv/lib/python3.6/site-packages/sqlalchemy/sql/visitors.py", line 79, in _compiler_dispatch 
     raise exc.UnsupportedCompilationError(visitor, cls) 
    sqlalchemy.exc.UnsupportedCompilationError: Compiler <sqlalchemy.sql.compiler.StrSQLCompiler object at 0x105b55be0> can't render element of type <class 'sqlalchemy.dialects.postgresql.dml.OnConflictDoUpdate'> 

我是什么丁错了？有没有更好的方法来做一个upsert？

谢谢！

Answer 1

您正试图获得Insert -object有没有适当的绑定，如果我们写

db_uri = make_url('your-postgres-db-uri-here') 
engine = create_engine(db_uri) 
upser_stmt.bind = engine 
print(upser_stmt) 

它的工作原理

我们还可以用绑定指定

insert_stmt = sqlalchemy.dialects.postgresql.insert(stock_table, 
                bind=engine).values(stock_today) 
upser_stmt = insert_stmt.on_conflict_do_update(
    index_elements=['date', 'product_id'], 
    set_=stock_today.to_dict(orient='dict') 
) 

创建插入语句的字符串表示