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Creating Meaningful Test Data
Language(s):SQL Server
Category(s):Generating Test Data
Whether you are a developer or work in QA, you have probably encountered the problem of a blank database that needs to be seeded for development or testing. This article will show you an easy way to use the SQL Server RAND function to generate a table of names that looks real but isn't.

-- =============================================

-- Author:          Jon Vote

-- Create date: 2015-01-11

-- Description:     Create Names

-- =============================================

Create PROCEDURE [dbo].[CreateNames]

       @NumRecords int = 1000

AS

BEGIN

       SET NOCOUNT ON;

       Declare @NumFirstNames int = (Select Max(Id) from FirstNames);

       Declare @FirstNameId int;

       Declare @FirstName nvarchar(50);

      

       Declare @Gender char;

       Declare @NumLastNames int = (Select MAX(Id) from LastNames);

       Declare @LastNameId int;

       Declare @LastName nvarchar(50);

       Declare @MiddleInitial varchar(1);

      

       Declare @DOB Date;

       Declare @NumDays int;

      

       Declare @SSN varchar(11);

       Declare @Count int = @NumRecords;

       while @Count > 0 begin

             set @FirstNameId = RAND() * @NumFirstNames + 1;

             set @LastNameId = RAND() * @NumLastNames + 1;

             Select @FirstName   =      FirstName,

                           @Gender =           Gender

             From   FirstNames

             Where  Id = @FirstNameId;

             Select @LastName = LastName

             From   LastNames

             Where  Id = @LastNameId;

             Declare @Matches int = 1;

             While @Matches > 0 begin

                    Set @SSN = convert(varchar, convert(int, RAND() * 10))

                                  + convert(varchar, convert(int, RAND() * 10))

                                  + convert(varchar, convert(int, RAND() * 10))

                                  + '-'

                                  + convert(varchar, convert(int, RAND() * 10))

                                  + convert(varchar, convert(int, RAND() * 10))

                                  + '-'

                                  + convert(varchar, convert(int, RAND() * 10))

                                  + convert(varchar, convert(int, RAND() * 10))

                                  + convert(varchar, convert(int, RAND() * 10))

                                  + convert(varchar, convert(int, RAND() * 10));

                    Set @Matches = (Select Count(*) From Names where SSN = @SSN);

             end

             Set @NumDays = RAND() * 50 * 365;

             Set @DOB = DateAdd(Day, @NumDays, '1950-01-01');

            

             Set @MiddleInitial = Char(RAND() * 26 + ASCII('A'));

             Insert Into         Names

                                        (

                                               FirstName,

                                               LastName,

                                               MiddleInitial,

                                               Gender,

                                               DOB,

                                               SSN

                                        )

             Values              (

                                               @FirstName,

                                               @LastName,

                                               @MiddleInitial,

                                               @Gender,

                                               @DOB,

                                               @SSN

                                        );

             Set @Count = @Count - 1;

       end;

END

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