Re: issue with connecting ms sql azure

Hello, James,

as you suggested, I tried to modify source code in both DBD::Sybase and 
freetds. I have modified struct imp_dbh_st in dbdimp.h (DBD::Sybase 
level) by adding one more field there, int directConn, and also updated 
dbdimp.c file correspondingly.

at freetds level, I may need to modify struct CS_CONNECTION, which is 
very important as the bridge connecting  sybase  and freetds, and also 
need to add one more definition, CS_DIRECT_CONN, to the list of existing 
CS_XXXXXX, such as CS_HOSTNAME, CS_USERNAME, etc.  However, I just could 
not find the place defining the struct and those CS_XXXXX. I searched 
all source code files of DBD:Sybase and freetds, and not luck.

Could you please give me some hints which file I should look for?

Thank you very much and have a good weekend.


Andy Qian




On 09/29/2011 07:30 PM, James K. Lowden wrote:
> On Thu, 29 Sep 2011 17:46:30 -0700
> Andy Qian<[email protected]>  wrote:
>
>> By tracing TDSDUMP info of connecting to other version ms sql server,
>> I found it looks like that DBD::Sybase always logins to master
>> database firstly, and then switches to the database specified in the
>> dsn string by executing "use $database" statement.
> To use Azure in Perl, you have to do one of two things:
>
> 1.  use DBD::ODBC, or
> 2.  hack FreeTDS's ct-lib&  DBD::Sybase
>
> As you may know, DBD::Sybase uses Client-Library, a/k/a ct-lib.
> ct-lib's ct_connect() function takes a server name only, no database
> name.  As you found out, the server initially connects the user
> to the master database, then changes to the user's database, as
> determined by the user's default database on that server.  If another
> is wanted, the client application can change it.  AFAIK there's no
> ct-lib connection setting or function to change the default database;
> the application simply sends "use<dbname>".
>
> For those following along at home: "use<dbname>" comes too late for
> Azure. Azure has no (or, at least, denies logins to) the master
> database.  The client must specify the database name at the time
> when logging in.
>
> How does ODBC do it?  ODBC sets the dbname in the login packet, which
> the server honors.
>
> When someone else wanted to use db-lib with Azure, I added a feature to
> the LOGINREC structure that lets the user set the dbname before calling
> dbopen().  The effect is to set the dbname in the login packet,
> something db-lib wouldn't otherwise do.
>
> To make it work in ct-lib, you'll have to do something similar.  Then,
> once there's a way to set the dbname in a ct-lib login packet, you'll
> have to modify DBD::Sybase to DTRT when the dbname appears in the
> connection string.
>
> Just a small matter of programming.
>
> --jkl
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