Questions about connecting to databases...difficult stuff :)

[Fursten]

Hi,

I would like to make a questions about the way Crystal reports comunicate with databases.

I know that Crystal have it´s own dlls to connect to some databases. They call it "Direct access".

What i would like to know about this is:

1) Do you think this is a good option?
2) In case of using it with Access, are we impliciting saying that we are always using DAO too? It seems that the dll that Crystal uses to "direct connection" is dependent on DAO... does this have changed in newer versions?

3) In the second case (accessing Access databases) is that true that we are limited to small databases (64k of memory)?



Now this is about using ODBC with Crystal. It is sayed (uhh by who? ) that Crystal uses, for some databases) merant drivers.... What are they... When does we know that we are using merant drivers instead of real ODBC drivers and vice-versa?

I would like some opinions on this...
thank you

 

[synapsevampire]

What version of Crystal are you using?

The Direct Access tends to be the fastest, and that is usually my primary consideration. Since you're using an MS Access database, you probably don't have to worry much about this, assuming that it's a small database.

As for DAO or whatever is used, this is Access you're considering, I think that the overhead of the driver is negligible compared to the speed of the database, or lack thereof, and you're completely insulated from DAO.

The CR drivers are prefixed by "CR".

-k

http://www.informeddatadecisions.com

kai@informeddatadecisions.com

 

[userr]

Hi

I´m using version 8.0

Can you give me a concrete exemple on how dou you establish a direct connection? For instance, is Database/Add Database to report... what option would you use for direct connect to Access?

Thank you!

 

[dgillz]

To add an access database top your report, click on database, add database to report, and navigate directly to the .mdb file. You will then be able to pick what tables you want on the report, linking. etc.

I do not believe there is a limit on small databases. I directly access btrieve tables all the time working with Macola and some of them are huge - over 6 million records is the biggest I have ever done.

The downside to a direct or native connection is that you cannot perform grouping on the server, you cannot use SQL expression fields, and you are limited to linking multiple tables only if the "to" field is indexed. There are some other limitations ai am sure but I cannot recall any off the top of my head.

I use ODBC to read databases most of the time. I do not know how (or if) ADO or DAO comes into play. Software Training and Support for Macola, Crystal Reports and Goldmine
251-621-8972
dgilsdorf@mchsi.com