List:General Discussion« Previous MessageNext Message »
From:Mike G Date:June 3 2002 5:06pm
Subject:Updating stock data
View as plain text  
I have a database containing stock data which I want to keep up to date.

The relevant fields are the symbol, date, high, low, and last prices.

When a new price comes in for an existing date, I want to update the high if the price is
higher, the low if the price is lower, and I always want to update the last price.

If a price comes in with a new date, I want to insert a new record and put the price into
the high, low, and last price fields.

The way I'm doing it now works, but I'm not sure it's best.

Basically, I look to see whether the currect date exists by retrieving the high and low
for the date. If it succeeds, I calculate whether the new price is higher than the
existing high or lower than the existing low. Then I update the high, low and last price.

If the date retreival fails, I do an insert.

My questions are:

1) is there a way to do either an insert or an update and not have to check if a bar
exists first? Should I use replace and it is just as quick?

2) Is there a way to update the highs and lows in one SQL statement without having to
fetch any info from the database first?


MySQL crash on ALTER TABLE commandDavid W. Archbold3 Jun
  • Updating stock dataMike G3 Jun
    • Re: Updating stock dataKeith C. Ivey3 Jun