Voice of the DBA

Author: way0utwest

  • Parameter Fun

    Recently I was editing a document about SQL Server on Linux and the author noted that if you type “sqlcmd” without any parameters, you get the list of possible parameters back. I tried that on my Windows laptop and immediately got an error that no credentials were supplied. Apparently sqlcmd on Windows attempts to connect to the default instance.

    I thought the author had made an error, but sure enough, when I connected to Linux and ran just “sqlcmd”, I got a list of parameters. What was more fascinating to me was that if I ran “sqlcmd -?” on either platform, I got the parameter list, as I would expect. However, if I ran “sqlcmd /?”, this worked on Windows, but returned an error on Linux.

    A long time ago I wrote some command line utilities to help our network team manage a Netware 3.x environment. I was proud of my work and knew that the team would appreciate a few of my tools. When I first showed me boss and started to explain what it did, he stopped me and ran the name of the utility with a /? at the end. Nothing returned, and he told me to redo the work and ensure that /? always returned help for the tool.

    I’ve kept that habit for years and I’ve often tried that with new programs. Most have worked, including bcp and sqlcmd. Somehow, that hasn’t continued to this day. For sqlcmd.exe on Linux, only -? works. If you run Docker, you need a –help, though -help works. Other programs might be more strict, but it’s surprising to me how many different ways we’ve implemented help and parameters.

    PowerShell has Get-Help, but then uses single dashes for parameters. A number of newer cli tools, especially for Linux, seem to want two dashes for parameters, though a single dash often works. I’ve seen a few tools that mix single and double dashes, depending on which parameter. I did find this note that on Unix a few single dash parameters can be combined, so the double dash indicates we are using one parameter, not multiple ones. That makes sense, though I would argue that -abc meaning -a -b -c is a fundamental design problem in and of itself.

    The evolution of help and parameters seems funny to me. It’s likely caused by someone implementing the parameter short cutting in Unix at some point that now requires double dashes for multi-character parameters, which is really a case of a short-sighted design in Unix. In any case, understanding the behavior of parameters and help is a useful skill, especially in the current environment that tends to implement more scripts with command line utilities.

    Steve Jones

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( 4.1MB) podcast or subscribe to the feed at iTunes and Libsyn.

  • The Android Car

    I’ve been a car guy for most of my life, admiring them, owning quite a few (20+), and enjoying lots of time behind the wheel of a vehicle. I’ve been lucky enough to own my dream car for a few years and even had the chance to drive a few unusual cards. While I haven’t driven a Tesla, I have ridden in one when the pedal was mashed to the floorboard (thanks, @GlennAlanBerry). That’s quite an experience, and one I’d recommend if you don’t have heart issues.

    This week I ran across a note that Volvo’s spin-off brand, Polestar, was unveiling an all electric car. This is their answer to a changing world where it seems every manufacturer wants to combat Tesla with an electric version of something. I might consider the Porsche Macan in an all electric version at some point, but the Polestar 2 is interesting for a reason besides the electric drive train. It’s the first production car that is build around Google’s Android system as the operating system for the car. There are entertainment systems using Android Auto, but this is a step higher.

    What I find interesting, and perhaps disturbing, is this move to more electronic integration for our vehicles, and the potential for issues if the operating system fails. I already think that we’ve built a few too many integrations in mechanical cars at times, where we can’t easily open doors, tow cars, or more if the electrical system fails. While I trust a plane or ship more because they are better maintained by mechanics, I worry about the durability and potential issues with updates for cars that are in daily use by users that might not take the best car of them. After all, people drive every day with small mechanical issues. I worry what this will mean for autos.

    There’s also the trust that we must have in both Google and Volvo to ensure that security is tight, patches are extremely well tested, and perhaps just as important, our privacy is respected. Google already gathers lots of data about us; do we want to give them more about how lifestyle? Will they sell data to insurance companies or others? I don’t know what other data might be captured, but I do worry that there are issues I haven’t considered, especially around security. Maybe even more disconcerting might be the charges for keys, updates, and more that will get added onto already expensive vehicles. What if systems become locked down to the point that only vendor mechanics can work on them?

    I like the idea of better designed and more efficient vehicles, and think that all electric is the future. This despite my longing for a manual transmission in my next car. However, I’m not quite sure I’m ready to trust a phone operating system to run lots of parts of my car. Already I think there ought to be open-source, embedded systems for any mechanical control  and security features that are completely separate from entertainment, without any access to the outside world. While I like DevOps and innovative software, what I worry about is the focus from many companies on features and costs, and not on security and quality.

    Steve Jones

  • Practical Web Scraping–More Reading

    As part of my learning goals for 2018, I wanted to work through various books. This is part of  my work with Python.

    It’s the end of the month, and I’m behind. I know it’s a short month, but it’s not that short. I had time to read the last couple week and I did some reading, but I didn’t get much practice.

    First the positive, then the excuses.

    Reading

    I did manage to read through the basic tutorial in Part I for how to use he BeautifulSoup module to read through an http page. This provided more ideas for finding sections of code and extracting out sections.

    I started Part II, which talks about more in depth http, with forms and posting. I’m still inside that one, and as of this point, I’m only 30% through the book.

    The plan for this weekend is to stop and practice a bit from BeautifulSoup and see what I can accomplish by reading a few web pages.

    Life Gets in the Way

    This month I had two long events on weekends that ate into my reading/working time, as well as a work project. I’m in the middle of volleyball season, and February brought me two 3 day tournaments to coach or watch. One was coaching a 13 year old team, and that occupied a lot of time. The evenings were spent with other coaches and I didn’t bring a laptop because I knew time would be limited. Add to that the need to get a few things done before and after the trip and I couldn’t practice web scraping.

    The second trip was for my daughter, and apart from watching her, my wife was in charge of team activities and I had to help. I had my laptop, but again, no time. I also chose to enjoy some time with my wife in the evening, which was worth it.

    Work was busy. We’re trying to migrate SQLServerCentral to a new platform and I’ve had to test things, as well as try and get other work done. As a result, I’ve been busy during the week and couldn’t even make time to incorporate any web scraping into my job. I also had to get other work done, so it’s been too busy to do much learning.

  • Schema Security

    How many of you grant access to schemas in your databases? I’m curious because I slowly am starting to see more and more people using schemas in their designs and not defaulting every object to “dbo”. That was the default action for many developers for years, and it’s still a habit of mine. Without SQL Prompt to add the schema to my queries, I’d still be producing code that followed that practice.

    Schemas exist to allow some separation of different types of objects. In early versions of SQL Server, we didn’t have schemas, but considered the third of four part naming to be the owner. In other RDBMSes, the use of a schema was to allow grouping and separation of different objects. This was also, and still is, a security boundary that helps ensure that authorized users can be easily limited to data access for certain objects.

    This is also a nice organizational boundary for related objects that have the same schema, or even name. I have seen auditing or etl schemas that maintain the same named table that exists in a dbo schema, but is separated by placing this in a separate schema. I have even seen some archiving schemas that move data to a related table that exists in a different schema, making it easy for new administrators and developers to find (or remove) older data.

    This week, let us know if you manage objects and security with schemas or if you stick to granting access at a database/object level the two more common ways of working with databases. If you have never used schemas and stuck with the defaults, perhaps you want to learn a bit more about how schemas work and the ways in which they may make your work easier.

    Steve Jones

    The Voice of the DBA Podcast

    Listen to the MP3 Audio ( 2.9MB) podcast or subscribe to the feed at iTunes and Libsyn.