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db内の(指定)データの確認exist?

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db内のデータの確認exist?(引数も可能)

使い方

  モデル.exist?(条件)

例:

Pagesテーブルに1件でもデータは存在するか確認
*引数を渡さないで使用

Page.exists?
# SELECT 1 FROM "pages" LIMIT 1

categoryがrailsであるデータが存在するか確認

Page.exists?(:category => "rails")
# SELECT 1 FROM "pages" WHERE "pages"."category" = "rails" LIMIT 1
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