Skip to main content

Microsoft's EF Tutorial: Seeding Your Database

Quick note on a solution to what could have been a game-breaking problem.  Was building out Microsoft's tutorial app for .NET Core with the EF Framework and got to the section on seeding the database.  To set up your connection string, you get the following line of code:

(In Startup.cs)

public void ConfigureServices(IServiceCollection services)
{
 services.AddDbContext<SchoolContext>(
  options =>
  options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"))
);
 services.AddMvc();
}

When I ran my build, in conjunction with the other seeding stuff the tutorial gives you, I got all sorts of errors.  For example, I would set up my connection string as follows:

server=localhost;user=root;password=root;database=mydb;port=3306

And get an error: "Keyword is not supported: port."

I panicked.  Microsoft's system for building out the database wasn't going to work, and I was going to have to figure out a workaround using EF migrations.  But after some searching, I found this.

The problem is the line UseSqlServer (and copying blindly).  Because I'm not using SqlServer, I'm using MySql.  So just change that to UseMySql and everything runs smoothly.  Whew!

Comments

Popular posts from this blog

Getting Geodata From Google's API

The apps I'm going to be analyzing are part of Dr. Charles Severance's MOOC on Python and Databases and work together according to the following structure (which applies both in this specific case and more generally to any application that creates and interprets a database using online data). The data source, in this case, is Google's Google Maps Geocoding API.  The "package" has two components: geoload.py  and geodump.py .  geoload.py  reads a list of locations from a file -- addresses for which we would like geographical information -- requests information about them from Google, and stores the information on a database ( geodata.db ).  geodump.py  reads and parses data from the database in JSON, then loads that into a javascript file.  The javascript is then used to create a web page on which the data is visualized as a series of points on the world-map.  Dr. Severance's course focuses on Python, so I'm only going to work my way through ...

Compiling and Executing Java Files With -cp

I decided I was going to "man up" and figure out how to compile a java program with an external dependency from the command line instead of relying on an IDE-- the DOS command line, to be more specific. I ran into a few problems: 1.  The external dependency was given to me as a java file.  I experimented compiling it as a .jar, but I wasn't sure how to import a class from a .jar, so I ended up compiling it into a class. 2.  When I tried to run the file, I got an error saying that the class had been compiled with a different version of Java than my JRE.  The Internet told me to check my path variable for Java.  It sure looked like it was pointing to the latest JRE (and the same version of Java as my compiler).  I asked the Internet again and found the following command: for %I in (java.exe) do @echo %~$PATH:I I'm not exactly sure what the syntax of that magic command is (intuitively it's returning the path that executes when I run the "java" com...

Throughput, Latency, and Pipelines: Diagnosis Of A Fallacy

Source here . Latency is the time it takes for a job to complete from start to finish -- for example, if we're downloading a file from a server, we might define the latency of the download as the amount of time it takes from the initial request for the file to the time the last byte is received. Throughput is a measure of how much can be completed in a given time.  Following the same example, how many files could we download in an hour? What is the relationship between latency and throughput?   It make take, again, 1 hour to download a file.  Notice already that we have a relationship between some amount of work that can be completed and time -- if the file is, say, 2 GB, it takes 1 hour to download 2 GB in our example.  What we really want to do here is generalize: how long does it take to download 10 GB?  How many GB can we download in ten hours or one minute?  Generalizing over time, we derive latency; generalizing over work completed, we derive the...