通俗易懂數倉建模—Inmon範式建模與Kimball維度建模

{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#6a737d","name":"user"}}],"text":"在數據倉庫領域，有兩位大師，一位是“數據倉庫”之父 Bill Inmon，一位是數據倉庫權威專家 Ralph Kimball，兩位大師每人都有一本經典著作，Inmon大師著作《數據倉庫》及Kimball大師的《數倉工具箱》，兩本書也代表了兩種不同的數倉建設模式，這兩種架構模式支撐了數據倉庫以及商業智能近二十年的發展。今天我們就來聊下這兩種建模方式——範式建模和維度建模。","attrs":{}}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"本文開始先簡單理解兩種建模的核心思想，然後根據一個具體的例子，分別使用這兩種建模方式進行建模，大家便會一目瞭然！","attrs":{}}]},{"type":"heading","attrs":{"align":"center","level":2},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#48b378","name":"user"}}],"text":"一、兩種建模思想","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"對於 Inmon 和 Kimball 兩種建模方式可以長篇大論敘述，但理論是很枯燥的，尤其是晦澀難懂的文字，大家讀完估計也不會收穫太多，所以筆者根據自己的理解用通俗的語言提煉出最核心的概念。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#48b378","name":"user"}}],"text":"範式建模","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"範式建模是數倉之父 Inmon 所倡導的，“數據倉庫”這個詞就是這位大師所定義的，這種建模方式在範式理論上符合3NF，","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3976f2","name":"user"}}],"text":"這裏的3NF與OLTP中的3NF還是有點區別的","attrs":{}},{"type":"text","text":"：關係數據庫中的3NF是針對具體的業務流程的實體對象關係抽象，而數據倉庫的3NF是站在企業角度面向主題的抽象。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Inmon 模型從流程上看是","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"自上而下","attrs":{}},{"type":"text","text":"的，自上而下指的是數據的流向，“上”即數據的上游，“下”即數據的下游，即從分散異構的數據源 -> 數據倉庫 -> 數據集市。","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"以數據源頭爲導向","attrs":{}},{"type":"text","text":"，然後一步步探索獲取儘量符合預期的數據，因爲數據源往往是異構的，所以會更加強調數據的清洗工作，將數據抽取爲","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"實體-關係","attrs":{}},{"type":"text","text":"模型，並不強調事實表和維度表的概念。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#48b378","name":"user"}}],"text":"維度建模","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Kimball 模型從流程上看是自下而上的，即從數據集市-> 數據倉庫 -> 分散異構的數據源。Kimball 是","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"以最終任務爲導向","attrs":{}},{"type":"text","text":"，將數據按照目標拆分出不同的表需求，數據會抽取爲","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"事實-維度","attrs":{}},{"type":"text","text":"模型，","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"數據源經ETL轉化爲事實表和維度表導入數據集市","attrs":{}},{"type":"text","text":"，以星型模型或雪花模型等方式構建維度數據倉庫，架構體系中，數據集市與數據倉庫是緊密結合的，","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"數據集市是數據倉庫中一個邏輯上的主題域","attrs":{}},{"type":"text","text":"。","attrs":{}}]},{"type":"horizontalrule","attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"兩種建模方式的理論概念就簡單介紹到這，因爲純理論知識說再多，大家也可能有點迷惑，所以下面用一個具體的例子來實踐兩種建模方式。","attrs":{}}]},{"type":"heading","attrs":{"align":"center","level":2},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#48b378","name":"user"}}],"text":"二、兩種建模實踐","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"通過上一小節兩種建模核心思想，相信大家對這兩種建模方式已經有了大概的理解，接下來我們通過具體的例子，讓大家有具體的感受。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#48b378","name":"user"}}],"text":"以電商舉例","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"大家都網購過，知道購買物品的流程，因此以電商購物爲例，更易於大家的理解。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"真實的電商購物的流程較複雜，此處表數量和表字段做簡化處理。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"1. 源表的結構及數據","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"對於我們大數據平臺來說，源表指的電商系統中後臺數據庫中的表，這種表一般都是OLTP類型的表：","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"① 用戶信息表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/28/2833bb94c36ec8415d7477e27560f471.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"② 城市信息表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/a8/a841aed526fc58e1fb23686aa63c8294.png","alt":null,"title":"","style":[{"key":"width","value":"25%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"③ 用戶等級表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/bc/bca97775e7fcfb2eaccd77a637a6bfdc.png","alt":null,"title":"","style":[{"key":"width","value":"25%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"④ 用戶訂單表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/d7/d7a171619900ca51871903383a6c17fc.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"2. 使用 ","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3976f2","name":"user"}}],"text":"Inmon","attrs":{}},{"type":"text","marks":[{"type":"italic","attrs":{}}],"text":" ","attrs":{}},{"type":"text","text":"模式建模","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"使用 Inmon 模式對以上源表數據進行建模，需要將數據抽取爲","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"實體-關係","attrs":{}},{"type":"text","text":"模式，根據源表的數據，我們將表拆分爲：用戶實體表，訂單實體表，城市信息實體表，用戶與城市信息關係表，用戶與用戶等級關係表等多個子模塊：","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"① 用戶實體表：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"(注：ETL已過濾掉註銷用戶)","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/1c/1c6accd903f96ed6f4254e596f01339e.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"② 支付成功訂單實體表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/5f/5f7d109441912f164ff2efa2013d6e19.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"③ 城市信息實體表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/76/767867933781b370609df62db0f5e77c.png","alt":null,"title":"","style":[{"key":"width","value":"25%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"④ 訂單與用戶關係表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/5b/5bf7d7a2bf38055d31652869edc7bcc8.png","alt":null,"title":"","style":[{"key":"width","value":"25%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"⑤ 用戶與城市信息關係表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/b1/b19a5f13a56be2a8caf7a18ab8300ee2.png","alt":null,"title":"","style":[{"key":"width","value":"25%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"⑥ 用戶與用戶等級關係表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/a0/a0c320d0710be4099b12414b967173da.png","alt":null,"title":"","style":[{"key":"width","value":"25%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"通過以上我們可以發現，範式建模就是將源表抽取爲實體表，關係表，所以範式建模即是","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"實體關係（ER）模型","attrs":{}},{"type":"text","text":"。數據沒有冗餘，符合","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"三範式","attrs":{}},{"type":"text","text":"設計規範。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","text":"3. 使用 ","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3976f2","name":"user"}}],"text":"Kimball","attrs":{}},{"type":"text","text":" 模式建模","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"使用 Kimball 模式，需要將數據抽取爲","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"事實表和維度表","attrs":{}},{"type":"text","text":"，根據源表數據，我們將表拆分爲：訂單事實表，用戶維度表，城市信息維度表，用戶等級維度表。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"可以看出，","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"在 Kimball 的維度建模中，不需要單獨維護數據關係表，因爲關係已經冗餘在事實表和維度表中","attrs":{}},{"type":"text","text":"。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"① 支付成功訂單事實表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/8e/8ec2884bb95e77bb5649b43d08470b2d.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"② 用戶維度表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/9c/9c083e66365c6e9ba8b418705035681a.png","alt":null,"title":"","style":[{"key":"width","value":"100%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"③ 城市信息維度表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/ef/ef6dec41a8ffed9c8c3991a5ae80acd3.png","alt":null,"title":"","style":[{"key":"width","value":"25%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":5},"content":[{"type":"text","text":"④ 用戶等級維度表：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/03/03c832861d87a7a83f87aa7bde70820c.png","alt":null,"title":"","style":[{"key":"width","value":"25%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"我們用圖的方式將以上表之間的關係簡單展示出來：","attrs":{}}]},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/9a/9a2937db211368544f0f18a5dcf82e23.png","alt":"","title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"根據上圖，我們發現什麼，這不就是典型的","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}},{"type":"strong","attrs":{}}],"text":"雪花模式","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"嘛，其特點就是維度表可以擁有其他維度表。","attrs":{}}]},{"type":"heading","attrs":{"align":"center","level":2},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#48b378","name":"user"}}],"text":"三、兩種建模對比","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#48b378","name":"user"}}],"text":"兩種建模方式特點","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}},{"type":"strong","attrs":{}}],"text":"範式建模","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"：通過上一小節的具體例子可以看出範式建模的優點：能夠結合業務系統的數據模型，較方便的實現數據倉庫的模型；同一份數據只存放在一個地方，沒有數據冗餘，保證了數據一致性；數據解耦，方便維護。但同時也帶來了缺點：表的數量多；查詢時關聯表較多使得查詢性能降低。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}},{"type":"strong","attrs":{}}],"text":"維度建模","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"：模型結構簡單，面向分析，爲了提高查詢性能可以增加數據冗餘，反規範化的設計，開發週期短，能夠快速迭代。缺點就是數據會大量冗餘，預處理階段開銷大，後期維護麻煩；還有一個問題就是","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}},{"type":"strong","attrs":{}}],"text":"不能保證數據口徑一致性","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"，原因後面有講解。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3976f2","name":"user"}}],"text":"我們再來理解下維度建模","attrs":{}},{"type":"text","text":"：數據會抽取爲","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"事實-維度","attrs":{}},{"type":"text","text":"模型，","attrs":{}},{"type":"text","marks":[{"type":"strong","attrs":{}}],"text":"維度就是看待問題的角度","attrs":{}},{"type":"text","text":"，從不同的角度看待某個問題，就會得出不同的結論，而要得到這個結論，就需要事實表中的度量，何爲度量，就是事實表中數值類型的字段。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"例：某公司的各個商品在全國各地市的銷售情況，維度就是全國的城市和各個商品，度量就是商品的單價，從不同的維度計算銷售額：如查看北京市酸奶的銷售額，上海市純牛奶的銷售額，這就是不同的維度組合方式。在限定的維度條件上，計算商品單價的總和，也就是 sum 度量值，即可得到我們想要的結果。","attrs":{}}]},{"type":"horizontalrule","attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"維度建模，就是依靠維度進行建模，但是如果維度設計的不合理，會不會帶來問題呢？","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"如果我們把省份當做一個單獨維度，城市當做一個維度，計算城市的人口數量。這時省份和城市都是單獨的維度，它們之間沒有了關係，就會出現以下情況：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"廣東省 杭州市 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Inmon 實體-關係的模式似乎並不能滿足快速迭代的業務需要。所以，","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}},{"type":"strong","attrs":{}}],"text":"互聯網公司更多場景下趨向於使用 Kimball 維度-事實的設計反而可以更快地完成任務","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"。","attrs":{}}]},{"type":"heading","attrs":{"align":"center","level":2},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#48b378","name":"user"}}],"text":"四、兩種建模混合場景","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"通過以上幾個小節我們已經理解了範式建模與維度建模的思想以及它們之間的異同，優缺點。那麼我們能不能將兩種建模方式混合使用呢，讓它們發揮各自最大的優勢。接下來我們一起來看下。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"範式建模必須符合準三範式設計規範，如果使用混合建模，則源表也需要符合範式建模的限制，即源數據須爲","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}},{"type":"strong","attrs":{}}],"text":"操作型","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"或","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}},{"type":"strong","attrs":{}}],"text":"事務型","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"系統的數據。通過ETL抽取轉換和加載到數據倉庫的ODS層，ODS層數據與源數據是保持一致的，所以ODS層數據也是符合範式設計規範的，","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}},{"type":"strong","attrs":{}}],"text":"通過ODS的數據，利用範式建模方法，建設原子數據的數據倉庫EDW，然後基於EDW，利用維度建模方法建設數據集市","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"結合兩種建模方式的各自規範，混合建模按照“","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}},{"type":"strong","attrs":{}}],"text":"松耦合、層次化","attrs":{}},{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"”的基本架構原則進行實施。混合數據倉庫架構方法主要包含以下關鍵步驟：業務需求分步構建、分層次保存數據、整合原子級的數據標準、維護一致性維度等。","attrs":{}}]},{"type":"horizontalrule","attrs":{}},{"type":"heading","attrs":{"align":null,"level":4},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"最後","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"color","attrs":{"color":"#3e3e3e","name":"user"}}],"text":"建模方式沒有好與壞之分，只有合適與不合適之分，在實際數倉建設中，需要靈活多變，不能全依賴建模理論，也不能不依賴。適時變通，才能建設一個好的數據倉庫。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"注：本文首發於InfoQ，禁止轉載。","attrs":{}}]}],"attrs":{}}]}