Question

我有一个bash脚本，可以通过电子邮件从远程数据库中删除一些记录。

for email in "$@"; do
heroku pg:psql << EOF
  DELETE FROM table1 WHERE email='$email';
  DELETE FROM table2 WHERE email='$email';
  DELETE FROM table2 WHERE email='$email';
EOF
done

当我执行它时，它当然有效但我连接多次到Heroku：

./scripts/delete-account.sh email1@example.com email2@example.com
---> Connecting to DATABASE_URL
DELETE 0
DELETE 0
DELETE 0
---> Connecting to DATABASE_URL
DELETE 0
DELETE 0
DELETE 0

有没有办法首先构建这个SQL语句然后立即执行它？

我知道我可以采用命令式方法，创建变量，在循环中修改它然后将其传递给pg:psql命令，但我不认为它是最好的和唯一的方法就是这样做。

Answer 1

为什么不使用脚本构建所有 SQL语句，然后将其传递给psql命令？

$cat ./scripts/delete-account.sh
(for email in "$@"; do
  echo "DELETE FROM table1 WHERE email='"$email"';"
  echo "DELETE FROM table2 WHERE email='"$email"';"
  echo "DELETE FROM table2 WHERE email='"$email"';"
done) | heroku pg:psql

然后将其命名为：

$./scripts/delete-account.sh email1@example.com email2@example.com

另外，注意引用，shell不会在单引号内插入

（尝试email=a@b.com;echo '$email'，看看会发生什么）。

如何迭代变量并构建单个命令来执行？

1 个答案: