2014-04-18T00:00:00.000Z

Randomizing Data

Ideally, development and testing data is reasonably robust to allow for realistic testing. Occasionally though, pulling in a copy of the production database is useful to hunt down specific cases. Personal information should be scrubbed from this though.

http://www.generatedata.com/ is a great tool for generating large amounts of random data. It’s easy to install a local copy too. Data sets can be saved and re-used. Large amounts of seed data for testing can also be created.

To replace existing columns with random data, its fairly straight forward to create an SQL script to do this.

USE YOUR_DATABASE_NAME

BEGIN TRANSACTION
GO

/* Drop temp table if exists. */
IF OBJECT_ID('tempdb..#RandomData') IS NOT NULL 
	DROP TABLE #RandomData
GO

/* Create the temp table. */
CREATE TABLE #RandomData (
    Id INTEGER NOT NULL IDENTITY(1, 1),
    FirstName NVARCHAR(255) NULL,
    LastName NVARCHAR(255) NULL,
    Street NVARCHAR(255) NULL,
    City NVARCHAR(255) NULL,
    PostalCode NVARCHAR(10) NULL,
    [State] NVARCHAR(50) NULL,
    Email NVARCHAR(255) NULL,
    Phone NVARCHAR(100) NULL,
    PRIMARY KEY (Id)
);
GO

/* Insert random data. This can be generated automatically from generatedata.com */
INSERT INTO #RandomData(FirstName,LastName,Street,City,PostalCode,State,Email,Phone) VALUES('Todd','Young','Ap #473-5868 Maecenas Avenue','Chandler','85414','AZ','id@sociisnatoquepenatibus.ca','(108) 354-7428');
/* ... Add more randomized data here .. */

GO

/* ------------------------------------------------------ */
/* Update tables from the temp table. */

UPDATE Registrants
SET
	Street = r.Street,
	City = r.City,
	PostalCode = r.PostalCode,
	State = r.[State],
	Email = r.Email,
	FirstName = r.FirstName,
	LastName = r.LastName,
	Phone = r.Phone
FROM Registrant.Transactions t
CROSS APPLY (
	SELECT TOP 1 *
	FROM #RandomData
	WHERE t.Id = t.Id   /* Yup, not a typo */
	ORDER BY NEWID()
) r


COMMIT TRANSACTION
GO

The general script runs as follows:

  • Create a temp table to store our random data for the duration of the transaction
  • Insert random data, generated from www.generatedata.com. This will need to be massaged a bit if going to MsSql.
  • Update appropriate tables and fields using CROSS APPLY
  • Woot! Data scrubbed!