Introduction to Sybase, Part 2
Last month, we installed a Sybase database server. This month, we will install a client to access our server. First, we need to understand how the Sybase network interface works.
A Sybase client must create a network connection to a database server when it needs to access resources in the database (see Figure 1). Sybase has created a protocol to communicate over the network. This protocol is called the Tabular Data Stream (TDS) protocol. It operates on top of other networking protocols such as TCP/IP on UNIX systems or IPX/SPX on Novell networks. TDS is a proprietary protocol and not documented by Sybase. Fortunately, Sybase has created client libraries which can be used to communicate with the server. A group of people have tried to reverse-engineer the TDS protocol. Look at http://sunsite.unc.edu/freetds/ for more information.
Sybase supports two interfaces to the database. DB-Library is an API that has been used for quite awhile in Sybase products. I believe it is supported for backwards compatibility, and may not be supported in a future version of the product. CT-Library is the API Sybase created for version 10 and higher products. It supports advanced features such as cursors and asynchronous query processing. You don't need to understand these features to do basic processing with your database server. We will use CT-Library to communicate with our server.
We could write our client using C or C++. The libraries required to do this are included with the server. Look for examples in the sample directory under the server directory. There is a subdirectory for DB-Library and one for CT-Library. We don't have to use C or C++, however. An extension to the Perl language called sybperl enables the use of Perl to write clients to access the database.
Most Linux distributions come with the Perl language. On my system, I have installed Red Hat 5.1 which includes Perl version 5 by default. Fortunately, it is possible to install sybperl without recompiling Perl. Using this method precludes the use of the DB-Library, which is why we have chosen to use CT-Library.
If Perl is not installed on your system, install it now. If your distribution does not provide perl, you can download the source from CPAN (http://www.cpan.org/).
First, we must download sybperl from http://www.perl.com/CPAN-local/authors/Michael_Peppler/
The newest version available at the time of this writing is version 2.09_05 in the file sybperl-2.09_05.tar.gz (148KB). Change directories to the location of the sybperl tar file, and issue the command:
Change to the sybperl directory just created, and edit the CONFIG file. In the line DBLIBVS=1000, change the 1000 to 0. Make sure the line SYBASE=/opt/sybase contains the correct directory for the Sybase server. The line EXTRA_LIBS=-ltli must be changed to EXTRA_LIBS=-linsck.
We will build sybperl to work with CT-library. Most Linux distributions come with the Berkeley DB library. If Perl is configured to use this library, a conflict arises when using DB-library at the same time, since both use the call open_database. If you recompile Perl to leave out the Berkeley DB library, you can leave the line DBLIBVS=1000 in the CONFIG file and use DB-library.
Save the changes to the CONFIG file, then issue this command:
This will create a file that will build the software. It looks for the Perl installation in your path. If Perl isn't in your path, you'll need to change your path to include it. Now issue the make command to build the software; it will take a few minutes to run. sybperl has tests that can be run to ensure it is built properly. To run these tests, edit the PWD file to put your sa password and the name of your Sybase server on the proper lines. If you installed the server following the directions in the last issue, the name of the server is linux_dev. Save the file, then type the command
make testThis command will run a series of tests. If everything is working properly, the message “All tests successful” will be printed.
Now, let's install sybperl. If your Perl installation is in a directory that requires root access to modify, change to root using su. Run the command
Perl and sybperl are now installed, so it is time to write some programs.
Practical Task Scheduling Deployment
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
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|SUSE LLC's SUSE Manager||Jul 21, 2016|
|My +1 Sword of Productivity||Jul 20, 2016|
|Non-Linux FOSS: Caffeine!||Jul 19, 2016|
|Murat Yener and Onur Dundar's Expert Android Studio (Wrox)||Jul 18, 2016|
- Stunnel Security for Oracle
- The Firebird Project's Firebird Relational Database
- SUSE LLC's SUSE Manager
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- Managing Linux Using Puppet
- My +1 Sword of Productivity
- Non-Linux FOSS: Caffeine!
- Google's SwiftShader Released
- SuperTuxKart 0.9.2 Released
- Doing for User Space What We Did for Kernel Space
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