Voice of the DBA

Category: Blog

Using OPENROWSET in SQL Server on Linux
I wanted to import the million song dataset in SQL Server on Linux. There’s a github repo that has the SQL to allow you to use this with the graph database features. However, it’s built for Windows.

Linux is a slightly different beast. Once I started down this path, I had memories of working on SunOS in college, messing with permissions and moving files.

I run Ubuntu in VMWare, so I first downloaded the files to my Documents folder. That’s pretty easy. However, once there, the mssql user can’t read them. Rather than mess with permissions for my home, I decided to move these to a location where the mssql user could read them.

First, I need to use mv to move the files. However, the default location for SQL Server (/var/opt/mssql) doesn’t let me drop files in there. Instead, I need to sudo the mv.
```
sudo mv unique_tracks.txt /var/opt/mssql/unique_tracks.txt
```
I repeated this for each file.

However, I still had permissions errors. Files have their own permissions in Linux, so I needed to alter those. I decided to use chown since these are temp files the SQL Server will use and once imported, I’ll delete them.
```
chown mssql unique_tracks.txt
```
From here, I could easily run the OPENROWSET commands and get the data loaded. Now to play around with a graph.
June 21, 2017
Speaking at the Data Platform Summit 2017

I am honored to be speaking at the Data Platform Summit 2017. The event takes place August 17-19, 2017 in Bangalore, India. This will be my first trip to India, and I’m excited to be traveling halfway around the world (literally 12:30 hours difference) to speak at this event.

I’ve got a pre-con on Aug 16, and then a few sessions during the main conference. If you have the chance, register and come. I’ve heard good things about the event and I look forward to seeing some of you there.

See if you can pick me out of the Teaser Video:

June 20, 2017
DevOps – Downloading a File from the Internet with PoSh

One of the things we need to do as data professionals is move data files around. Often we’ll get a local path, but in looking for public data sets, I wanted to get a file from the Internet. In this case, a rather large file.

I could have put the URL in a browser, but the file was slow to load, and while waiting ten minutes or so for the download to complete and doing a “Save As” is quick, it isn’t easily repeatable. Plus, since I needed to get a few files, and might need to do it again, I thought a PoSh download would be better.

A quick search turned up a few options. I could use System.Net.WebClient, or I could use Invoke-WebRequest. I decided to use the latter because it could use credentials or even parse the file prior to doing some save.

I just had a simple item, so I used:

Invoke-WebRequest -Uri “http://labrosa.ee.columbia.edu/millionsong/sites/default/files/AdditionalFiles/unique_tracks.txt” -OutFile “e:\Downloads\unique_tracks.txt”

I could easily have wrapped this in a function to simulate a copy command, and I may do that at some point. For now, I can drop this in a file, copy/paste, and change a few filenames.

If this were part of a regular process, such as getting files from a remote web server, I could easily automate this in a task on some server. For now, this is a quick, easy way to get a file from the Internet without a browser.

June 19, 2017
Renaming MDF/LDF Files–SQLNewBlogger
Another post for me that is simple and hopefully serves as an example for people trying to get blogging as #SQLNewBloggers.

I would guess many people would run into this situation at some point. A developer or DBA creates a database, then decides to rename it, but the logical and physical names aren’t correct. This post will look at how to do this. A couple of notes and then the process below.

This might not matter to many of you, but in development, I sometimes find I’ll rename a database and then attempt to recreate (or deploy) a new database with the old name. The mdf/ldf files don’t match, and I realize it’s because I’m using defaults.

However, I’d also say this is an issue in a DR situation. If the filenames don’t seem to match, someone might restore the wrong database or the wrong files. Or worse, think the can delete a file on the file system because there’s no database with that name.

Renaming the Database

This is easy. Right click, select Rename.

Then type the name name. In this case, I’m going from WideWorldImporters-SSDT to WideWorldImporters-RR.

That renames the database, but what about the files? If I run this:
```
sp_helpdb ‘WideWorldImporters-RR’
```
I get this:

Not really what I want. I need these mdf/ldf files to be changed. How do I do this?

I can get to the properties for the database and select the “Files” pane to get a list of files. Here I can change the logical name by clicking that field and typing a new name. I’ve done that here.

However, if I scroll to the right to the File Name column, I can’t change anything.

What I need to do is use the ALTER DATABASE command with the MODIFY FILE command. I need to do this twice.
1. Change the physical file name
2. Change the logical file name
Let’s do that. Here’s the code to change the physical name.
```
ALTER DATABASE [WideWorldImporters-RR]
 MODIFY FILE
 (   NAME = 'WideWorldImporters-SSDT_Data',
     FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL13.SQL2016\MSSQL\DATA\WideWorldImporters-RR.mdf'
 );
```
I need to repeat this for the log file and the MOT file. Once I change the names, I get this message.

This is key. If I were to restart my system now, when the database attempted to start and go through recovery, the files would not have been found. Now, I need to change the physical file names.

To do that, I first need to take the database offline.
```
USE master
go
ALTER DATABASE [WideWorldImporters-RR] SET OFFLINE
```
Then I go to the location of the physical files and rename them in Windows Explorer.

Now I bring the database online.
```
ALTER DATABASE [WideWorldImporters-RR] SET ONLINE
```
Once that’s done, I can then use ALTER DATABASE again to change the logical file names.
```
ALTER DATABASE [WideWorldImporters-RR]
  MODIFY FILE (NAME='USERDATA_612671E2',
               NEWNAME = 'WWI_UserData'
               );
```
And run a final sp_helpdb.

SQLNewBlogger

An easy task, with a touch of research in Books Online, but not too difficult. This took me about 10 minutes to do, and since I realized this was a good skill, I took screenshots and saved code as I went.

Then about 10 minutes to write this up.
June 15, 2017