SQL Server 2005 - Generate Keys

On my comptuer, this code generates 1,000,000 keys in 1:30 minutes

There are many ways to generate keys, this code generates by alternating between alpha characters and numeric characters.

Code:

---

-- =============================================
-- Author:        <Michael Ciurescu>
-- Create date: <20090124>
-- Description:        <Generate Keys in dbo.NewKeys table>
-- =============================================
/*
-- Our NewKeys table:

CREATE TABLE [dbo].[NewKeys](
        [KeyID] INT IDENTITY(1,1) NOT NULL,
        [Key] VARCHAR(50) NOT NULL,
        CONSTRAINT [PK_NewKeys] PRIMARY KEY NONCLUSTERED ([KeyID] ASC)
)

CREATE UNIQUE CLUSTERED INDEX [IN_NewKeys_Key] ON [dbo].[NewKeys] ([Key] ASC)
*/
CREATE PROCEDURE [dbo].[spx_CreateKeys]
                  @TotalKeys INT
                , @KeyLength INT
                , @Recursive INT = 10
AS
BEGIN
        SET NOCOUNT ON;
       
        /*
                spx_CreateKeys 1000000, 7, 10
               
                SELECT TOP 10000 * FROM dbo.NewKeys ORDER BY KeyID
                SELECT TOP 10000 * FROM dbo.NewKeys ORDER BY KeyID DESC
               
                ALTER INDEX ALL ON dbo.NewKeys REBUILD
               
                TRUNCATE TABLE dbo.NewKeys
        */
        DECLARE @i INT
                , @q INT
                , @Key VARCHAR(50)
                , @AlphaNum VARCHAR(40)
                , @NumAlpha VARCHAR(40)
                , @TotalInserted INT
                , @StartTime DATETIME
                , @EndTime DATETIME
                , @RecordsPerSec FLOAT
                , @TotalDeleted INT
       
        -- create our temp table where our keys will be inserted first
        DECLARE @TmpKeys TABLE (ID INT PRIMARY KEY IDENTITY(1,1), [Key] VARCHAR(50))
        --DECLARE @DelKeys TABLE (ID INT PRIMARY KEY, [Key] VARCHAR(50))
       
        SET @StartTime = GetDate()
        SET @AlphaNum = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
        SET @NumAlpha = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
       
        SET @i = 1
        WHILE @i <= @TotalKeys BEGIN
                -- depending on your requirments, this section you should change
                SET @q = 0
                SET @Key = ''
                WHILE @q <= @KeyLength BEGIN
                        SET @Key = @Key + SUBSTRING(@AlphaNum, CONVERT(INT, 26 * RAND(CHECKSUM(NEWID())) + 1), 1)
                                                        + SUBSTRING(@NumAlpha, CONVERT(INT, 10 * RAND(CHECKSUM(NEWID())) + 1), 1)
                        SET @q = @q + 2
                END
               
                INSERT INTO @TmpKeys
                SELECT CASE WHEN CONVERT(INT, 2 * RAND(CHECKSUM(NEWID()))) = 0 THEN
                                LEFT(@Key, @KeyLength) ELSE SUBSTRING(@Key, 2, @KeyLength) END
               
                SET @i = @i + 1
        END
       
        -- Delete duplicate keys from the temp table
        DELETE t
--                OUTPUT DELETED.ID, DELETED.[Key]
--                INTO @DelKeys
        FROM @TmpKeys AS t
        INNER JOIN (
                SELECT MIN(ID) AS MinID, [Key]
                FROM @TmpKeys
                GROUP BY [Key]
                HAVING Count(*) > 1
        ) AS d ON t.[Key] = d.[Key]
        WHERE d.MinID <> t.ID
       
        -- Insert only new keys into dbo.NewKeys table (no duplicates)
        INSERT INTO dbo.NewKeys ([Key])
        SELECT t.[Key]
        FROM @TmpKeys AS t
                LEFT JOIN dbo.NewKeys AS n ON t.[Key] = n.[Key]
        WHERE n.[Key] IS NULL
        ORDER BY t.ID
       
        SET @TotalInserted = @@ROWCOUNT
       
        -- calculate speed
        SET @EndTime = GetDate()
        SET @RecordsPerSec = CASE WHEN DATEDIFF(ms, @StartTime, @EndTime) > 0 THEN
                                                1000.0 * @TotalInserted / DATEDIFF(ms, @StartTime, @EndTime) ELSE NULL END
       
        SET @TotalDeleted = @TotalKeys - @TotalInserted
        SET @Recursive = @Recursive - 1
       
        -- execute again if we have less keys than we should (i.e. if there were duplicates)
        IF ISNULL(@Recursive, 0) > 0 AND @TotalDeleted > 0
                EXEC dbo.spx_CreateKeys @TotalDeleted, @KeyLength, @Recursive
       
        -- diplay info on what was done
        SELECT @TotalInserted AS [Records Inserted]
                , @TotalDeleted AS [Total Deleted]
                , @RecordsPerSec AS [Keys / Second]
                , DATEDIFF(ms, @StartTime, @EndTime) / 1000.0 AS [Duration]
END

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