{"version":"1.0","description":"\u4e00\u610f\u6027(UNIQUE)\u5236\u7d04\u306fNULL\u3067\u306a\u3044\u5024\u306b\u5bfe\u3057\u3066\u3060\u3051\u52b9\u304f\u3001\u305d\u3046\u601d\u3063\u3066\u3044\u305f\u9803\u304c\u79c1\u306b\u3082\u3042\u308a\u307e\u3057\u305f\u2026 SQL Server\u306fNULL\u3082\u4e00\u610f\u6027\u5236\u7d04\u306e\u5bfe\u8c61\u306b\u306a\u308a\u307e\u3059\u3002NULL\u306b\u306a\u3063\u3066\u3044\u308b\u884c\u304c\u8907\u6570\u3042\u308b\u3068\u91cd\u8907\u3060\u3068\u5224\u5b9a\u3055\u308c\u307e\u3059\u3002SQL-92\u306e\u898f\u683c\u66f8\u3092\u3042\u305f\u3063\u3066\u307f\u308b\u3068\u3001\u3053\u308c\u306f\u5b8c\u5168\u306a\u898f\u683c\u9055\u53cd\u306a\u3093\u3067\u3059\u3051\u3069\u306d\u3002 A unique constraint is satisfied if and only if no two rows in a table have the same non-null values in the unique columns. http://www.contrib.andrew.cmu.\u2026","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fcs.hatenablog.jp%2Fentry%2F2013%2F08%2F21%2F200809\" title=\"SQL Server\u3067\u3082\u8ad6\u7406\u524a\u9664\u3068\u4e00\u610f\u6027\u5236\u7d04\u3092\u4e21\u7acb - C Sharpens you up\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","height":"190","provider_url":"https://hatena.blog","title":"SQL Server\u3067\u3082\u8ad6\u7406\u524a\u9664\u3068\u4e00\u610f\u6027\u5236\u7d04\u3092\u4e21\u7acb","image_url":null,"width":"100%","author_url":"https://blog.hatena.ne.jp/Sampo/","type":"rich","categories":["SQL"],"url":"https://cs.hatenablog.jp/entry/2013/08/21/200809","blog_url":"https://cs.hatenablog.jp/","author_name":"Sampo","blog_title":"C Sharpens you up","published":"2013-08-21 20:08:09","provider_name":"Hatena Blog"}