如何规范化SQL数据库

Question

我想知道是否有人对如何规范化数据库有任何建议。现在，我不是要设计结构，而是要实际将数据库数据从旧结构移动到新的规范化结构。我知道我可以编写类似PHP脚本的内容，但是我想知道是否有一种方法可以在SQL中进行。特别是MySQL。

**编辑：有人尝试过SwisSQL吗？这是一个迁移工具，但我不确定它是否能满足我的要求。

Answer 1

这是在脚本中标准化表的示例。我建议你做这样的事情

e.g Table: tbl_tmpData
Date, ProductName, ProductCode, ProductType, MarketDescription, Units, Value
2010-01-01, 'Arnotts Biscuits', '01', 'Biscuit', 'Store 1', 20, 20.00
2010-01-02, 'Arnotts Biscuits', '01', 'Biscuit', 'Store 2', 40, 40.00
2010-01-03, 'Arnotts Biscuits', '01', 'Biscuit', 'Store 3', 40, 40.00
2010-01-01, 'Cola', '02', 'Drink', 'Store 1', 40, 80.00
2010-01-02, 'Cola', '02', 'Drink', 'Store 2', 20, 40.00
2010-01-03, 'Cola', '02', 'Drink', 'Store 2', 60, 120.00
2010-01-01, 'Simiri Gum', '03', 'Gum', 'Store 1', 40, 80.00
2010-01-02, 'Simiri Gum', '03', 'Gum', 'Store 2', 20, 40.00
2010-01-03, 'Simiri Gum', '03', 'Gum', 'Store 3', 60, 120.00

您将首先创建日期表：

CREATE TABLE tbl_Date
(
DateID int PRIMARY KEY IDENTITY(1,1)
 ,DateValue datetime
)

INSERT INTO tbl_Date (DateValue)
SELECT DISTINCT Date
FROM tbl_Data
WHERE Date NOT IN (SELECT DISTINCT DateValue FROM tbl_Date)

然后，您将创建您的市场表

CREATE TABLE tbl_Market
(
MarketID int PRIMARY KEY IDENTITY(1,1)
 ,MarketName varchar(200)
)

INSERT INTO tbl_Market (MarketName)
SELECT DISTINCT MarketDescription
FROM tbl_tmpData
WHERE MarketName NOT IN (SELECT DISTINCT MarketDescription FROM tbl_Market)

然后，您将创建您的ProductType表

CREATE TABLE tbl_ProductType
(
ProductTypeID int PRIMARY KEY IDENTITY(1,1)
 ,ProductType varchar(200)
)

INSERT INTO tbl_ProductType (ProductType)
SELECT DISTINCT ProductType
FROM tbl_tmpData
WHERE ProductType NOT IN (SELECT DISTINCT ProductType FROM tbl_ProductType)

然后，您将创建您的产品表

CREATE TABLE tbl_Product
(
ProductID int PRIMARY KEY IDENTITY(1,1)
, ProductCode varchar(100)
, ProductDescription varchar(300)
 ,ProductType int
)

INSERT INTO tbl_Product (ProductCode, ProductDescription, ProductType)
SELECT DISTINCT tmp.ProductCode,tmp.ProductName, pt.ProductType
FROM tbl_tmpData tmp
INNER JOIN tbl_ProductType pt ON tmp.ProductType = pt.ProductType
WHERE ProductCode NOT IN (SELECT DISTINCT ProductCode FROM tbl_Product)

然后，您将创建数据表

CREATE TABLE tbl_Data
(
DataID int PRIMARY KEY IDENTITY(1,1)
, DateID varchar(100)
, ProductID varchar(100)
, MarketID varchar(300)
 ,Units decimal(10,5)
 , value decimal(10,5)
)


INSERT INTO tbl_Data (ProductID, MarketID, Units, Value)
SELECT t.DateID
       , p.ProductID
       , m.MarketID
       , SUM(tmp.Units)
       , SUM(tmp.VALUE)
FROM tbl_tmpData tmp
INNER JOIN tbl_Date t ON tmp.Date = t.DateValue
INNER JOIN tbl_Product p ON tmp.ProductCode = p.ProductCode
INNER JOIN tbl_Market m ON tmp.MarketDescription = m.MarketName 
GROUP BY t.DateID, p.ProductID, m.MarketID
ORDER BY t.DateID, p.ProductID, m.MarketID