如何确保所有 sql 语句都执行 else rollback

Question

我很少SQL陈述。

copy into STG_PB(VAR,FILE_NAME, LINE_NUMBER) 
  from (
      select ,metadata$filename, metadata$file_row_number
      from @investor_stage_s3// 
)

delete from stg_pb1
insert into stg_pb1 values (....)

因此，我每天都会从 s3 获取大量数据并加载到数据库中。在我的 SQL 语句中，我使用了删除语句，因此如果我在插入语句中遇到任何错误，我之前的所有数据都将丢失。如果发生错误，我如何确定回滚到以前的数据？

谢谢，习

Answer 1

使用transactions：

A transaction is a sequence of SQL statements that are processed as an atomic unit. All statements in the transaction are either applied (i.e. committed) or undone (i.e. rolled back) together.

和 Allowing Statement Errors to Abort Transactions:

To allow a statement error within a transaction to abort the transaction, set the TRANSACTION_ABORT_ON_ERROR parameter at the session or account level.

ALTER SESSION SET TRANSACTION_ABORT_ON_ERROR = TRUE;

BEGIN TRANSACTION;
-- DML 1
-- DML 2
COMMIT;

用 Snowflake 脚本块包装所有内容：

CREATE OR REPLACE TABLE t1(i INT);

EXECUTE IMMEDIATE $$
BEGIN
  BEGIN TRANSACTION;
  
  INSERT INTO t1 SELECT 1;
  INSERT INTO t1 SELECT 1/0;
  
  COMMIT;
  RETURN 'Success';
EXCEPTION
  WHEN OTHER THEN
  ROLLBACK;
  RETURN 'Error';
END;
$$;

SHOW TRANSACTIONS;
SELECT * FROM t1;

如何确保所有 sql 语句都执行 else rollback

How to make sure all sql statements are executed else roolback

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