Read Pervasive Database 9 without creating ODBC DS

问题:

I am writing an application in C# (.NET 4.0) which has to integrate with another, much older application. Part of the requirement is that my program must read data from three Btrieve files. I can assume that these Btrieve data files will already exist on the computers where my program is installed, and I can also assume that Pervasive PSQL V9 will also be installed and the relational and transactional service programs are running.

I have the associated DDF files, and I can install them as part of my application. The way they were created I have to put them in a different directory to where the Btrieve data files are. (They have to be a sub-directory of the directory where the data files are).

I didn't know anything about Pervasive or Btrieve when I started, but after a bit of experimentation I have got to the point where I can create a DSN using the 32 bit ODBC administration tool, and I can read from the data files using the ODBC ADO connector. All good so far.

My question is, is it possible to read from these files from my .NET program without having to create an ODBC DSN on the machine? In other words, is it possible to specify the directory where the *.DAT files are and the directory where the *.DDF files are in the ODBC connection string?

I'm not committed to using ODBC, I'm happy to use OLEDB or any other technology that allows me to reliably read from these files using .NET.

回答1:

While a DSN-less connection allows your to connect without a DSN, you would still need a Database Name. Pervasive Database Names can be created on the fly using DTI or DTO. Using C#, I would suggest DTO.
If you can't create a Database Name, you can use OLEDB. It supports using a path in the Data Source parameter of the connection string as documented in the Remote Connections section of the OLEDB documentation.

One more caveat, make sure to compile your .NET program as x86 and not AnyCPU. The Pervasive OLEDB provider is only 32 bit. If you install your app on a 64 bit Operating System compiled as AnyCPU, it will look for a 64 bit provider and fail.

回答2:

You should search for DSN-less connection. Instead of passing DSN=mydsn to the connect method (where mydsn is the DSN you set up) you pass DRIVER=xxx (where xxx is the name of the driver) and any other attributes it needs to direct it at the files. There are loads of sites with lists of connection strings for different ODBC drivers so one is bound to list Pervasive if you cannot locate the documentation for your ODBC driver. Another alternative to so look at your DSN in the registry where you'll find the names of the attributes you need to specify.