Question

我正在尝试向postgresql jsonb列添加部分索引。 jsonb列的名称为： email_provider 。我已尝试在列上添加部分索引，如下所示，但它会抛出不同的错误，例如 PG :: UndefinedColumn：错误：列“email_povider”不存在，有时它会引发错误： PG :: AmbiguousFunction：错误：运算符不唯一：未知 - ＆gt;未知

rails-5 迁移中的部分索引如下所示：

add_index  :accounts, :name, name:  "index_accounts_on_email_provider_kind", using: :gin, where: "('email_provider' -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com') AND ('email_povider' -> 'amazon ses' ->> 'smtp_host' = 'www.awses.com')"

email_provider列的json如下所示：

 {
   "email_provider": {
     "sparkpost": {
        "smtp_host": "www.sparkpost.com",
        "smtp_port": ""
      },
      "aws ses": {
        "smtp_host": "www.amazon/ses.com ",
        "smtp_port": " ",
        "username": " ",
        "password": " "
      }
  }
}

表格如下：

class CreateAccounts < ActiveRecord::Migration[5.0]
   def change
      create_table :accounts do |t|
        t.string :name, null: false
        t.jsonb :email_provider, null: false
        t.jsonb :social_account, default: '[]', null: false
        t.timestamps
   end
      add_index  :accounts, :name, name: "index_accounts_on_email_provider_kind", using: :gin, where: "('email_provider' -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com') AND ('email_povider' -> 'amazon ses' ->> 'smtp_host' = 'www.awses.com')"

      add_index  :accounts, :name, name: "index_accounts_on_social_account_type", using: :gin, where: " 'social_account' @> [{'type': 'facebook'}] AND 'social_account' @> [{'type': 'twitter'}]"
   end
end

更新

根据对下面接受的答案的轻微调整，我在rails activerecord中用于创建 btree 而非 gin 索引的代码如下所示。它创建了一个btree索引，因为我们使用的是字符串数据类型的名称列而不是here描述的jsonb：

add_index :accounts, :name, name: "index_accounts_on_name_email_provider", where: "email_provider -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com' AND email_provider -> 'amazon ses' ->> 'smtp_host' = 'www.awses.com' " add_index :accounts, :name, name: "index_accounts_on_name_social_account", where: " social_account @> '[{\"type\": \"facebook\"}]'::jsonb AND social_account @> '[{\"type\": \"twitter\"}]'::jsonb"

Answer 1

我认为你需要这样的东西：

add_index :accounts, :email_provider, name:  "index_accounts_on_email_provider_kind", using: :gin, where: "(email_provider -> 'email_provider' -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com') AND (email_provider -> 'email_povider' -> 'amazon ses' ->> 'smtp_host' = 'www.awses.com')"

我已将add_index的第二个参数更改为:email_provider，因为这是列名。另外，对于where子句，我改变了

'email_provider' -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com'

到

email_provider -> 'email_provider' -> 'sparkpost' ->> 'smtp_host' = 'www.sparkpost.com'

因为->运算符期望它将参数保留为json（b）值，但是您提供了一个字符串。所以例如email_provider -> 'email_provider'从名为email_provider的列中提取与email_provider对应的值。请注意，最后一行可以更紧凑地编写为：

email_provider #>> '{email_provider,sparkpost,smtp_host}' = 'www.sparkpost.com'

使用从{josn（b）对象中提取“路径”的#>>。所以add_index语句可以写成：

add_index :accounts, :email_provider, name:  "index_accounts_on_email_provider_kind", using: :gin, where: "(email_provider #>> '{email_provider,sparkpost,smtp_host}' = 'www.sparkpost.com') AND (email_provider -> '{email_povider,amazon ses,smtp_host}' = 'www.awses.com')"

对于你的第二个索引，你应该尝试类似：

where: " social_account -> 'social_account' @> '[{\"type\": \"facebook\"}]'::jsonb AND social_account -> 'social_account' @> '[{\"type\": \"twitter\"}]'::jsonb"

在这种情况下，我在第一种情况下对列进行了同样的思考。我还更改了@>的正确参数，它必须是jsonb值。因此，您必须将其定义为JSON字符串，这需要字符串的双引号（还要注意我们必须为ruby转义它们），然后我将该字符串转换为jsonb以获得所需类型。

为postgresql jsonb字段创建部分索引

1 个答案: