模拟实现SQL Server字段列显示的数据类型

IF OBJECT_ID(N‘[dbo].[ufn_GetDisplayDataTypeName]‘, ‘FN‘) IS NOT NULL
BEGIN
    DROP FUNCTION [dbo].[ufn_GetDisplayDataTypeName];
END
GO
 
--==================================
-- 功能: 获取字段列显示的数据类型名称
-- 说明: 支持用户定义类型，可以运行于SQL Server 2005+
-- 创建: yyyy-MM-dd hh:mm-hh:mm XXX 创建内容描述
-- 修改: yyyy-MM-dd hh:mm-hh:mm XXX 修改内容描述
--==================================
CREATE FUNCTION [dbo].[ufn_GetDisplayDataTypeName]
(     
     @intUserTypeID AS INT                -- 用户类型ID
    ,@sntMaxLength AS SMALLINT            -- 最大字节长度
    ,@tntPrecision AS TINYINT            -- 精度
    ,@tntScale AS TINYINT               -- 小数位
    ,@bitIsUpperDisplay AS BIT = 0        -- 是否大写显示（默认小写显示）
) RETURNS NVARCHAR(270)
AS
BEGIN
    SET @bitIsUpperDisplay = ISNULL(@bitIsUpperDisplay, 0);
 
    DECLARE
         @nvcDataTypeName AS NVARCHAR(128)
        ,@nvcBaseDataTypeName AS NVARCHAR(128)
        ,@nvcSuffixDisplayName AS NVARCHAR(14)
    SELECT
         @nvcDataTypeName = N‘‘
        ,@nvcBaseDataTypeName = N‘‘
        ,@nvcSuffixDisplayName = N‘‘
 
    SELECT
         @nvcDataTypeName = [name]
        ,@nvcBaseDataTypeName = (CASE WHEN (@nvcDataTypeName = N‘sysname‘ OR [is_user_defined] = 1) THEN TYPE_NAME([system_type_id]) ELSE @nvcDataTypeName END)
    FROM 
        [sys].[types]
    WHERE 
        [user_type_id] = @intUserTypeID;
 
   SET @nvcDataTypeName = (CASE WHEN @nvcDataTypeName <> @nvcBaseDataTypeName THEN @nvcDataTypeName + N‘:‘ ELSE N‘‘ END);
 
   SET @nvcBaseDataTypeName = CASE @bitIsUpperDisplay WHEN 1 THEN UPPER(@nvcBaseDataTypeName) ELSE @nvcBaseDataTypeName END;
 
   SET @nvcSuffixDisplayName = (CASE
        WHEN @nvcBaseDataTypeName = N‘char‘ THEN QUOTENAME(RTRIM(CAST(@sntMaxLength AS VARCHAR(4))), N‘)‘)
        WHEN @nvcBaseDataTypeName = N‘varchar‘ THEN (CASE WHEN @sntMaxLength = -1 THEN N‘(MAX)‘  ELSE QUOTENAME(RTRIM(CAST(@sntMaxLength AS VARCHAR(4))), N‘)‘) END)
        WHEN @nvcBaseDataTypeName = N‘nchar‘ THEN QUOTENAME(RTRIM(CAST(@sntMaxLength / 2 AS VARCHAR(4))), N‘)‘)
        WHEN @nvcBaseDataTypeName = N‘nvarchar‘ THEN (CASE WHEN @sntMaxLength = -1 THEN N‘(MAX)‘  ELSE QUOTENAME(RTRIM(CAST(@sntMaxLength / 2 AS VARCHAR(4))), N‘)‘) END)
        WHEN @nvcBaseDataTypeName = N‘binary‘ THEN QUOTENAME(RTRIM(CAST(@sntMaxLength AS VARCHAR(4))), N‘)‘)
        WHEN @nvcBaseDataTypeName = N‘varbinary‘ THEN (CASE WHEN @sntMaxLength = -1 THEN N‘(MAX)‘  ELSE QUOTENAME(RTRIM(CAST(@sntMaxLength / 2 AS VARCHAR(4))), N‘)‘) END)
        WHEN @nvcBaseDataTypeName IN (N‘numeric‘, N‘decimal‘) THEN QUOTENAME(RTRIM(CAST(@tntPrecision AS VARCHAR(4))) + N‘,‘ + RTRIM(CAST(@tntScale AS VARCHAR(4))), N‘)‘)
        WHEN @nvcBaseDataTypeName IN (N‘time‘, N‘datetime2‘, N‘datetimeoffset‘) THEN QUOTENAME(RTRIM(CAST(@tntScale AS VARCHAR(4))), N‘)‘)
        ELSE N‘‘ END);
 
    RETURN @nvcDataTypeName + @nvcBaseDataTypeName + @nvcSuffixDisplayName;
END
GO

CREATE TYPE [dbo].[fd_udt_digest] FROM [NVARCHAR](255) NULL
GO
 
CREATE TYPE [dbo].[fd_udt_id] FROM [CHAR](15) NOT NULL
GO
 
CREATE TYPE [dbo].[fd_udt_username] FROM [NVARCHAR](20) NULL
GO
 
CREATE TYPE [dbo].[UFemail] FROM [VARCHAR](100) NULL
GO
 
CREATE TYPE [dbo].[UFFlag] FROM [CHAR](1) NULL
GO
 
CREATE TYPE [dbo].[UFhyperlink] FROM [VARCHAR](100) NULL
GO
 
CREATE TYPE [dbo].[UFMedia] FROM [IMAGE] NULL
GO
 
CREATE TYPE [dbo].[UFreference] FROM [VARCHAR](30) NULL
GO
 
CREATE TYPE [dbo].[UFtext] FROM [NTEXT] NULL
GO
 
CREATE TYPE [dbo].[UFUID] FROM [UNIQUEIDENTIFIER] NULL
GO
 
CREATE TYPE [dbo].[userdecimal] FROM [DECIMAL](28, 6) NOT NULL
GO
 
CREATE TYPE [dbo].[udtProduct] AS TABLE 
(
     ProductID INT NOT NULL
    ,UnitPrice DECIMAL(9, 2) NOT NULL 
    ,Quantity INT NOT NULL
    PRIMARY KEY ([ProductID] ASC)
)
GO
 
CREATE TABLE [dbo].[ScaleDataTypeTable](
    [ColDecimal] [NUMERIC](18, 2) NULL,
    [ColNumeric] [NUMERIC](9, 2) NULL,
    [ColFloat] [FLOAT] NULL,
    [ColReal] [REAL] NULL,
    [ColTime] [TIME](5) NOT NULL,
    [ColDateTime2] [DATETIME2](3) NULL,
    [ColDateTimeOffset] [DATETIMEOFFSET](5) NULL,
    [ColSqlVariant] [SQL_VARIANT] NULL,
    [ColMoney] [MONEY] NULL,
    [ColSmallMoney] [SMALLMONEY] NULL,
    [Col1] [dbo].[fd_udt_digest] NULL,
    [Col2] [dbo].[fd_udt_id] NULL,
    [Col3] [dbo].[fd_udt_username] NULL,
    [Col4] [dbo].[UFemail] NULL,
    [Col5] [dbo].[UFFlag] NULL,
    [Col6] [dbo].[UFhyperlink] NULL,
    [Col7] [dbo].[UFMedia] NULL,
    [Col8] [dbo].[UFreference] NULL,
    [Col9] [dbo].[UFtext] NULL,
    [Col10] [dbo].[UFUID] NULL,
    [Col11] [dbo].[userdecimal] NULL,
    [Col12] HIERARCHYID NULL,
    [Col13] GEOMETRY NULL,
    [Col14] GEOGRAPHY NOT NULL,
    [Col15] CHAR(10) NOT NULL,
    [Col16] VARCHAR(25) NOT NULL,
    [Col16Max] VARCHAR(MAX) NOT NULL,
    [Col17] NCHAR(16) NOT NULL,
    [Col18] NVARCHAR(32) NOT NULL,
    [Col18Max] NVARCHAR(MAX) NOT NULL,
    [ColBigint] BIGINT NOT NULL,
    [ColInt] INT NOT NULL,
    [ColSmallint] INT NOT NULL,
    [ColTinyint] TINYINT NOT NULL,
    [ColBit] BIT NOT NULL,
    [Col19] DECIMAL(9,7) NOT NULL,
    [Col20] MONEY NOT NULL,
    [Col21] SMALLMONEY NOT NULL,
    [Col22] TIMESTAMP NOT NULL,    
    [Col24] UNIQUEIDENTIFIER NOT NULL,
    [Col25] IMAGE NOT NULL,
    [Col26] TEXT NOT NULL,
    [Col27] NTEXT NOT NULL,
    [Col28] BINARY(8) NOT NULL,
    [Col29] VARBINARY(8) NOT NULL,
    [Col29Max] VARBINARY(MAX) NOT NULL,
    [ColMxml] XML NULL,
    [Col30] DATE NOT NULL,
    [Col31] DATETIME NOT NULL,
    [Col32] SMALLDATETIME NOT NULL
) ON [PRIMARY];
 
GO
 
CREATE TABLE [dbo].[UpdateDataTable]
(
    UpdateDataTableId INT NOT NULL,
    [Col23] ROWVERSION NOT NULL,
    [Colname] sysname NOT NULL
) ON [PRIMARY];
GO

SELECT 
     T2.[name] AS [table_name]
    ,[T1].[name] AS [column_name]
    ,TYPE_NAME([T1].[user_type_id]) AS [column_datatype]
    ,[dbo].[ufn_GetDisplayDataTypeName]([T1].[user_type_id], [T1].[max_length], [T1].[precision], [T1].[scale], 0) AS [column_display_datatype]
    ,[T1].[max_length]
    ,[T1].[precision]
    ,[T1].[scale]
 
FROM 
    [sys].[all_columns] AS T1
    INNER JOIN [sys].[all_objects] AS T2
        ON [T1].[object_id] = [T2].[object_id]
WHERE 
    [T2].[name] IN (N‘ScaleDataTypeTable‘, N‘UpdateDataTable‘)
    --AND EXISTS (SELECT 1 FROM [sys].[types] WHERE ([name] = N‘sysname‘ OR [is_user_defined] = 1) AND [user_type_id] = [T1].[user_type_id]);
GO

SELECT 
     T2.[name] AS [table_name]
    ,[T1].[name] AS [column_name]
    ,TYPE_NAME([T1].[user_type_id]) AS [column_datatype]
    ,[dbo].[ufn_GetDisplayDataTypeName]([T1].[user_type_id], [T1].[max_length], [T1].[precision], [T1].[scale], 1) AS [column_display_datatype]
    ,[T1].[max_length]
    ,[T1].[precision]
    ,[T1].[scale]
 
FROM 
    [sys].[all_columns] AS T1
    INNER JOIN [sys].[all_objects] AS T2
        ON [T1].[object_id] = [T2].[object_id]
WHERE 
    [T2].[name] IN (N‘ScaleDataTypeTable‘, N‘UpdateDataTable‘)
    --AND EXISTS (SELECT 1 FROM [sys].[types] WHERE ([name] = N‘sysname‘ OR [is_user_defined] = 1) AND [user_type_id] = [T1].[user_type_id]);
GO