SQL\u306e\u4e00\u3064\u306e\u7279\u5fb4\u306f\u6628\u65e5\u7d39\u4ecb\u3057\u305f\u3088\u3046\u306b\u5ba3\u8a00\u578b\u8a00\u8a9e\u3067\u3042\u308b\u3053\u3068\u3067\u3059\u304c\u3001\u3082\u3046\u4e00\u3064\u306f\u3001\u300c\u771f\u300d\u300c\u507d\u300d\u306e\u307b\u304b\u306b\u300c\u4e0d\u660e\u300d\u3092\u8a31\u3059\uff13\u5024\u8ad6\u7406\u3092\u4f7f\u7528\u3057\u3066\u3044\u308b\u3053\u3068\u3067\u3059\u3002\u3053\u308c\u306f\u3001SQL\u306e\u539f\u7406\u3092\u63d0\u6848\u3057\u305fE.F.Codd\u304c\u3053\u3060\u308f\u3063\u305f\u305d\u3046\u3067\u3059\u304c\u3001\u4e0d\u8a55\u3067\u3059\u3002
\n\u300c\u4e0d\u660e\u300d\u306f\u3001\u60c5\u5831\u4e0d\u8db3\u3067\u771f\u507d\u3092\u6c7a\u3081\u3089\u308c\u306a\u3044\u304b\u3001\u30c7\u30fc\u30bf\u305d\u306e\u3082\u306e\u304c\u4e00\u90e8\u6b20\u843d\u3057\u3066\u3044\u308b\u3068\u304d\u306b\u4f7f\u3046\u8a2d\u5b9a\u3067\u3059\u3002”null”\uff08\u30cc\u308b\u3001\u65e5\u672c\u8a9e\u3067\u3082\u30cc\u30eb\u3068\u3044\u3044\u307e\u3059\uff09\u3068\u3044\u3046\u4ed6\u306e\u8a00\u8a9e\u3067\u3082\u3088\u304f\u898b\u308b\u5358\u8a9e\u3067\u8868\u3057\u307e\u3059\u3002
\n\u300c\u771f\u300d\u3068\u300cnull\u300d\u306e\u8ad6\u7406\u548c\uff08or\uff09\u3092\u3068\u308b\u3068\u300c\u771f\u300d\u3067\u3059\u304c\u3001\u300c\u507d\u300d\u3068\u300cnull\u300d\u306e\u8ad6\u7406\u548c\u306f\u300cnull\u300d\u306b\u306a\u308a\u307e\u3059\u3002\u3053\u306e\u3088\u3046\u306b\u3001\u8ad6\u7406\u6f14\u7b97\u3092\u7e70\u308a\u8fd4\u3059\u3068\u300cnull\u300d\u304c\u5897\u6b96\u3057\u307e\u3059\u3002\u307e\u305f\u3001\u8db3\u3057\u7b97\u306a\u3069\u6570\u5024\u6f14\u7b97\u306e\u5de6\u8fba\u306b\u300cnull\u300d\u304c\u5165\u3063\u3066\u3044\u308b\u3068\u7d50\u679c\u3082null\u306b\u306a\u308a\u307e\u3059\u3002
\n\u307e\u305f\u3001\u300c\u6392\u4e2d\u5f8b\u300d\u304c\u4f7f\u3048\u306a\u304f\u306a\u308b\u554f\u984c\u3082\u3042\u308a\u307e\u3059\u3002\u300cA\u3067\u3042\u308b\u300d\u300cA\u3067\u306a\u3044\u300d\u306e\u307b\u304b\u306b\u300c\u4e0d\u660e\u300d\u3068\u3044\u3046\u7d50\u679c\u304c\u8a31\u3055\u308c\u308b\u306e\u3067\u3001\u80cc\u7406\u6cd5\u304c\u4f7f\u3048\u307e\u305b\u3093\u3002
\n\u6700\u8fd1\u3067\u306f\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u306e\u30c6\u30fc\u30d6\u30eb\uff08\u30a8\u30af\u30bb\u30eb\u306e\u8868\u3068\u601d\u3063\u3066\u3088\u3044\uff09\u306e\u6700\u521d\u306e\u8a2d\u5b9a\u6642\u306b\u300cnull\u3092\u8a31\u3055\u306a\u3044\u300d\u3068\u3044\u3046\u8a2d\u5b9a\u304c\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u3063\u3066\u3044\u307e\u3059\u3002
\n\u300cnull\u300d\u306f\u3001java\u306b\u3082\u3042\u308a\u307e\u3059\u304c\u3001\u3053\u3061\u3089\u306f\u53c2\u7167\u5148\u304c\u306a\u3044\u3068\u304d\u306bnull pointer exception\u3068\u3044\u3046\u30a8\u30e9\u30fc\u3092\u5410\u304d\u307e\u3059\u3002\u30cd\u30c3\u30c8\u30b9\u30e9\u30f3\u30b0\u306e\u300c\u306c\u308b\u307d\u300d\u306f\u3053\u3053\u304b\u3089\u6765\u3066\u3044\u308b\u305d\u3046\u3067\u3059\uff08\u3044\u307e\u306f\u3042\u307e\u308a\u898b\u307e\u305b\u3093\u304c\u3001\u4e00\u6642\u671f\u6d41\u884c\u308a\u307e\u3057\u305f\uff09\u3002
\nhttps:\/\/kotobank.jp\/word\/%E3%81%AC%E3%82%8B%E3%81%BD-188435
\n\u6700\u8fd1\u306fnull\u304c\u51fa\u306a\u3044\u3088\u3046\u306b\u3059\u308b\u30d7\u30ed\u30b0\u30e9\u30e0\u8a00\u8a9e\u304c\u3044\u308d\u3044\u308d\u958b\u767a\u3055\u308c\u3066\u3044\u307e\u3059(java\u306e”\u4e0a\u4f4d\u4e92\u63db”\u306ekotlin\u306a\u3069\u3002android\u30b9\u30de\u30db\u306e\u30a2\u30d7\u30ea\u3092\u4f5c\u308b\u306e\u306b\u4f7f\u308f\u308c\u307e\u3059\uff09\u3002
\nhttps:\/\/kotlinlang.org\/docs\/null-safety.html
\nSQL\u306e\uff13\u5024\u8ad6\u7406\u306b\u3064\u3044\u3066\u306f\u3001\u4e0b\u8a18\u304c\u9762\u767d\u304b\u3063\u305f\u3067\u3059\u3002
\nhttps:\/\/mickindex.sakura.ne.jp\/database\/db_3vl.html
\nwikipedia\u306e\u89e3\u8aac\u3082\u54f2\u5b66\uff08\uff1f\uff09\u3068\u3057\u3066\u9762\u767d\u3044\u3067\u3059\u3002
\nhttps:\/\/ja.wikipedia.org\/wiki\/3%E5%80%A4%E8%AB%96%E7%90%86<\/p>\n
\u82f1\u8a9e\u306f\u95a2\u9023\u306e\u8a00\u8449\u3092\u62fe\u3063\u3066\u307f\u307e\u3057\u3087\u3046\u3002https:\/\/en.wikipedia.org\/wiki\/Three-valued_logic\u3000\u3082\u898b\u3066\u3044\u307e\u3059\u3002<\/p>\n
\u4e0d\u8a55\u3067\u3059\u3000be unpopular, be unfavorably received, bring disrepute
\n\u6392\u4e2d\u5f8b\uff08\u306f\u3044\u3061\u3085\u3046\u308a\u3064\uff09\u3000law of excluded middle
\n\u8ad6\u7406\u548c\u3000logical sum, OR
\n\u8ad6\u7406\u7a4d\u3000logical product, logical multiply, AND
\n\u8ad6\u7406\u6f14\u7b97\u3000logical operation
\n\u7b97\u8853\u6f14\u7b97\u3000arithmetic operation
\n\u80cc\u7406\u6cd5\u3000reductio ad absurdum \u82f1\u8a9e\u3067\u306f\u30e9\u30c6\u30f3\u8a9e\u3092\u305d\u306e\u307e\u307e\u4f7f\u3044\u307e\u3059\u3002\u30ea\u300c\u30c0\u300d\u30af\u30c6\u30a3\u30aa\u30a6\u3000\u30a2\u30c9\u3000\u30a2\u30d6\u300c\u30b5\u300d\u30fc\u30c0\u30e0\u3000\u3000\u30cf\u30ea\u30fc\u30dd\u30c3\u30bf\u30fc\u306e\u546a\u6587\u306b\u3042\u308a\u305d\u3046\u3067\u3059\u3002\u3000\u82f1\u8a9e\u306b\u76f4\u3059\u3068\u3001reduction to absurdity \u3070\u304b\u3052\u305f\u3053\u3068\u306b\u9084\u5143\u3059\u308b
\n\u53c2\u7167\u3000reference
\n\u771f\u7406\u5024\u8868\u3000truth table
\n\u30d6\u30fc\u30eb\u4ee3\u6570\u3000Boolean algebra
\n\u30a6\u30ab\u30b7\u30a7\u30d3\u30c3\u30c1\u8ad6\u7406\u3000Lukasiewicz logic\u3000\u30003\u5024\u8ad6\u7406\u306e\u5b9a\u5f0f\u5316\u3067\u3059
\n\uff13\u5024\u8ad6\u7406\u3000ternary logic, three-valued logic, trivalent logic
\n\u5358\u9805\u6f14\u7b97\u5b50\uff08\u305f\u3093\u3053\u3046\u3048\u3093\u3056\u3093\u3057\uff09\u3000unary operators\u3000(not\u3001\u968e\u4e57\u306a\u3069\uff09
\n\u968e\u4e57\uff08\u304b\u3044\u3058\u3087\u3046\uff09\u3000factorial
\n\u30b2\u30fc\u30c7\u30eb\u306e\u4e0d\u5b8c\u5168\u6027\u5b9a\u7406 G\u00f6del’s incompleteness theorems \u300c\u305b\u300d\u30aa\u30ec\u30e0\u30ba\u3000\u3000\u3044\u304f\u3064\u304b\u3042\u308b\u306e\u3067\u8907\u6570\u3067\u3059\u306d\u3002\u3000\u3053\u306e\u8a3c\u660e\u306f\u7d50\u679c\u306e\u6df1\u9060\u3055\u306b\u6bd4\u3079\u308b\u3068\u96e3\u3057\u304f\u306a\u3044\u306e\u3067\u3001\u4e00\u5ea6\u89e3\u8aac(wikipedia\u65e5\u672c\u8a9e\u7248\u304c\u8a73\u3057\u3044\uff09\u3092\u8aad\u3093\u3067\u307f\u308b\u3068\u3044\u3044\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
SQL\u306e\u4e00\u3064\u306e\u7279\u5fb4\u306f\u6628\u65e5\u7d39\u4ecb\u3057\u305f\u3088\u3046\u306b\u5ba3\u8a00\u578b\u8a00\u8a9e\u3067\u3042\u308b\u3053\u3068\u3067\u3059\u304c\u3001\u3082\u3046\u4e00\u3064\u306f\u3001\u300c\u771f\u300d\u300c\u507d\u300d\u306e\u307b\u304b\u306b\u300c\u4e0d\u660e\u300d\u3092\u8a31\u3059\uff13\u5024\u8ad6\u7406\u3092\u4f7f\u7528\u3057\u3066\u3044\u308b\u3053\u3068\u3067\u3059\u3002\u3053\u308c\u306f\u3001SQL\u306e\u539f\u7406\u3092\u63d0\u6848\u3057\u305fE.F.Codd\u304c\u3053\u3060\u308f\u3063\u305f\u305d\u3046\u3067\u3059\u304c\u3001\u4e0d\u8a55\u3067\u3059\u3002 \u300c\u4e0d\u660e\u300d\u306f\u3001\u60c5\u5831\u4e0d\u8db3\u3067\u771f\u507d\u3092\u6c7a\u3081\u3089\u308c\u306a\u3044\u304b\u3001\u30c7\u30fc\u30bf\u305d\u306e\u3082\u306e\u304c\u4e00\u90e8\u6b20\u843d\u3057\u3066\u3044\u308b\u3068\u304d\u306b\u4f7f\u3046\u8a2d\u5b9a\u3067\u3059\u3002”null”\uff08\u30cc\u308b\u3001\u65e5\u672c\u8a9e\u3067\u3082\u30cc\u30eb\u3068\u3044\u3044\u307e\u3059\uff09\u3068\u3044\u3046\u4ed6\u306e\u8a00\u8a9e\u3067\u3082\u3088\u304f\u898b\u308b\u5358\u8a9e\u3067\u8868\u3057\u307e\u3059\u3002 \u300c\u771f\u300d\u3068\u300cnull\u300d\u306e\u8ad6\u7406\u548c\uff08or\uff09\u3092\u3068\u308b\u3068\u300c\u771f\u300d\u3067\u3059\u304c\u3001\u300c\u507d\u300d\u3068\u300cnull\u300d\u306e\u8ad6\u7406\u548c\u306f\u300cnull\u300d\u306b\u306a\u308a\u307e\u3059\u3002\u3053\u306e\u3088\u3046\u306b\u3001\u8ad6\u7406\u6f14\u7b97\u3092\u7e70\u308a\u8fd4\u3059\u3068\u300cnull\u300d\u304c\u5897\u6b96\u3057…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[60],"tags":[23],"class_list":["post-1947","post","type-post","status-publish","format-standard","hentry","category-computer","tag-computer"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.sekaiken.com\/index.php?rest_route=\/wp\/v2\/posts\/1947","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.sekaiken.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.sekaiken.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.sekaiken.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sekaiken.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1947"}],"version-history":[{"count":0,"href":"https:\/\/www.sekaiken.com\/index.php?rest_route=\/wp\/v2\/posts\/1947\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.sekaiken.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1947"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.sekaiken.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1947"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.sekaiken.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1947"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}