I've got an Access 2007 database and my first tries to establish a
connection were disappointing, failing in the
'open' stage : Error in SQLConnect [Microsoft][ODBC Driver Manager].
I'm new to that stuff and have no idea how to fix the problem. Both the
database and GRETL are in on my Windows 7 PC.
I would appreciate your help!!!
[mailto:firstname.lastname@example.org] Im Auftrag von Riccardo (Jack)
Gesendet: Samstag, 3. April 2010 10:33
An: Gretl list
Cc: Fernando Borraz
Betreff: Re: [Gretl-users] Manipulating a database
On Sat, 3 Apr 2010, Leandro Zipitria wrote:
Hello Gretl Community,
I have a database with daily prices which is in a rather unusual
format and I want to know if it is possibly to create a panel data with it
Gretl scripts. The database is extracted from a dbf archive, and its
has 6 variables:
- The (number of) supermarket from which the price is reported
- The (number of) the product which price is being reported
- The year of the price
- The month of the price
- The price reported itself
- The first day of the month the price is reported
- The last day of the month the price is reported
I have nearly one million rows with data, but in order to do some
use it as a panel- I will need to transform it in a
I suppose that the best way that Gretl can handle it is to create a
specific column for each product, and then stack all the supermarkets
on a daily basis. In this way, I will have each column representing a
first 700 rows being a price for each product for supermarket
1, the next 700 rows being a price for each product for supermarket 2, etc.
But in order to do it, I will need first to create the daily prices
series, which is now "compacted" in the datafile. I am attaching a random
10 elements from the database in order to get a better picture of the
situation. In the first sheet I submit the actual data format, on the second
one which I think should be the (best?) result.
I will first ask if this kind of transformation is possible in Gretl.
I am aware that running some scripts on other programs could do the trick,
think that it could be possible in Gretl to do it. But I am also think
that it could be rather complex to do it, and I am a new one on this issues.
1) Turning a dataset such as this into a panel dataset is not trivial from a
_conceptual_ point of view: what are your units? supermarkets or products?
or combinations of the two? What would you use as the time unit (day, month,
week)? If you choose anything longer than a day (say, a week), how would you
handle changes of prices during the week? Of course, this is a design
decision and gretl can't help you with this.
2) If you have your data in some database that can be queried via SQL, I
think that our ODBC apparatus may just fit your needs. You may want to have
a look at the corresponding chapter of the User's Guide.
Riccardo (Jack) Lucchetti
Dipartimento di Economia
Università Politecnica delle Marche