【发布时间】：2017-11-23 15:54:36
【问题描述】：
我正在将一个包含数百行的 CSV 导入我的 rails 数据库。
有时用户想强制覆盖数据，所以我认为最好销毁所有数据并重新开始。
类似：
account.catalog_listings.delete_all if should_refresh
CSV.foreach(file, options) do |row|
account.catalog_listings.create!({...rowstuff})
问题是delete_all 行引发了 PG 错误
ActiveRecord::StatementInvalid (PG::NotNullViolation: ERROR: null value in column "account_id" violates not-null constraint
DETAIL: Failing row contains (1, null, ... ... ).
: UPDATE "catalog_listings" SET "account_id" = NULL WHERE "catalog_listings"."account_id" = $1):
app/models/catalog_listing.rb:41:in `import_catalog_listings'
app/controllers/accounts_controller.rb:20:in `catalog'
我确实在几个外键字段上有一个null: false，但我不明白为什么delete_all 试图删除外键而不是删除整个记录？
更新 - 我更改后一切正常：
account.catalog_listings.delete_all if should_refresh
到：
account.catalog_listings.destroy_all if should_refresh
除了destroy 遍历每一项并逐一删除：
SQL (0.1ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 957]]
SQL (0.1ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 958]]
SQL (0.1ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 959]]
SQL (0.1ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 960]]
SQL (0.1ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 961]]
SQL (0.1ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 962]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 963]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 964]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 965]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 966]]
SQL (0.3ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 967]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 968]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 969]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 970]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 971]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 972]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 973]]
SQL (0.3ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 974]]
SQL (0.2ms) DELETE FROM "catalog_listings" WHERE "catalog_listings"."id" = $1 [["id", 975]]
不酷...有人知道更好的方法吗？
【问题讨论】：
-
您的模型中有
before_destroy过滤器吗？ -
没有。我有
belongs_to :account和validates_presence_of:account_id` -
导致问题的原因，主要是在数据库级别...您必须在迁移期间设置约束，对吧？
-
迁移是
t.integer account_id, null: false，仅此而已。真正的问题是为什么 rails 会删除 account_id 而不是删除对象。