It depends on what data you are looking for.
I developed my system by going to the State library and copying all the form guides and results for main venue races on the East coast of Australia for a period of 3 years.
I then entered every bit of data about the horses (55 items per horse !)into a datbase and then developed a program to add a weighting to each bit of data and try to match the winners of the races...it took 2 years to do that !...when I finished I had a formula that actually worked in real time and I was able to cut the number of data items to just 8 per horse..my system still works 5 years later..it's the only way to do it uless you are prepared to pay big $ for someone elses work...good luck.