{"description":"\u30ea\u30ec\u30fc\u30b7\u30e7\u30f3\u306e\u7406\u8ad6\u306f\u30c0\u30e1\u3060 - \u6a9c\u5c71\u6b63\u5e78\u306e\u30ad\u30de\u30a4\u30e9\u98fc\u80b2\u8a18 \u30e1\u30e2\u7de8\u306e\u7d9a\u304d\u3002 RVA\uff08relation valued attribute\uff09\u3063\u3066\u3001\u30db\u30f3\u30c8\u306b\u30d0\u30ab\u3058\u3083\u306a\u3044\u306e?! group-by\u306e\u7d50\u679c\u3092\u518d\u3073\u30ea\u30ec\u30fc\u30b7\u30e7\u30f3\u3068\u3057\u3066\u8868\u73fe\u3059\u308b\u305f\u3081\u306b\u5c0e\u5165\u3057\u305f\u3089\u3057\u3044\u304c\u3001\u306a\u3093\u3067\u305d\u3093\u306a\u30d0\u30ab\u306a\u3053\u3068\u3059\u308b\uff1f Rel(A, B) Map(A, Pow(B)) \u3063\u3066\u3060\u3051\u3058\u3083\u3093\u3002grf:Map(A, B)\u2192Pow(A\u00d7B) \u3068\u3044\u3046\u95a2\u6570\u30b0\u30e9\u30d5\u5199\u50cf\u3082\u4f7f\u3063\u3066\u3044\u308b\u304c\u3002Rel(A, B), Map(A, B) \u306a\u3069\u3092\u4f7f\u3046\u3053\u3068\u3092\u62d2\u3093\u3067\u3044\u308b\u304b\u3089\u3001\u3053\u3046\u3044\u3046\u60b2\u60e8\u306a\u3053\u3068\u306b\u306a\u308b\u3002 \u5c5e\u6027\u540d\u306b\u62d8\u308b\u304c\u3001\u305d\u306e\u7406\u7531\u306f\u6697\u9ed9\u306e\u30bb\u30de\u30f3\u30c6\u30a3\u30af\u30b9\u3092\u5c5e\u6027\u540d\u306b\u8fbc\u3081\u308b\u304b\u3089\u3002\u305d\u306e\u7d50\u2026","image_url":null,"provider_name":"Hatena Blog","provider_url":"https://hatena.blog","author_name":"m-hiyama-memo","type":"rich","url":"https://m-hiyama-memo.hatenablog.jp/entry/20171023/1508731427","width":"100%","version":"1.0","author_url":"https://blog.hatena.ne.jp/m-hiyama-memo/","title":"\u30ea\u30ec\u30fc\u30b7\u30e7\u30f3\u306e\u7406\u8ad6\u306f\u30c0\u30e1\u3060 (2)","blog_title":"(\u4fdd\u5b58\u7528) \u6a9c\u5c71\u6b63\u5e78\u306e\u30ad\u30de\u30a4\u30e9\u98fc\u80b2\u8a18 \u30e1\u30e2\u7de8","blog_url":"https://m-hiyama-memo.hatenablog.jp/","categories":["\u96d1\u8a18\uff0f\u5099\u5fd8","\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9","\u30c0\u30e1\u51fa\u3057","STEM"],"height":"190","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fm-hiyama-memo.hatenablog.jp%2Fentry%2F20171023%2F1508731427\" title=\"\u30ea\u30ec\u30fc\u30b7\u30e7\u30f3\u306e\u7406\u8ad6\u306f\u30c0\u30e1\u3060 (2) - (\u4fdd\u5b58\u7528) \u6a9c\u5c71\u6b63\u5e78\u306e\u30ad\u30de\u30a4\u30e9\u98fc\u80b2\u8a18 \u30e1\u30e2\u7de8\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","published":"2017-10-23 13:03:47"}