Im trying to compute a 24 hour rms (root mean squared) from a dataset stored in MySQL. I Need to grab the last 24 hours of points that occur within 24 hour period before a particular row offset. For instance if I wanted to compute 24hour rms for row id 1250 which has a timestamp of June 7th 2007 at midnight I would need to get all the po...
I hate writing migrations, but it's important for the schemas to stay in sync. What I'd much rather do is update my schema.rb and have Rails notice, then run something which generates the appropriate migration based on the difference between the old version and the current version. Is there a way I can do that? ...
Hi, I know what I asking might not make a lot of sense for C# experts but I'll explain what I want to do and then you can suggest me how to do it in a better way if you want ok? I have a C# class called DatabaseManager that deals with different MySQL queries (ado.net NET connector, not linq or any kind of ActiveRecord-ish library). I ...
Hi, I'm writing an online project asset tracker but I'm new to MySQL. What would be the best way of tracking projects, users, and assets for something like this? I have 3 tables for assets, users, and projects. Users should own projects and assets. Assets could be members of multiple projects, and projects should be able to be seen by mu...
How do I create and drop a database defined using Visual Studio Team System Database Edition from inside a unit test? (I guess that makes it more of a integration test...) I want to be able to create the database either for each test or for a suite of tests and then drop the database after each test or suite of tests. Is there an API I...
What you recommend for storing images in:- File System or Database This is conceptual question, I want to conclude, which approach is better in different projects. Note: please justify which approach is better. ...
Hello guys, I would like to ask what is the best way to execute a setup like the following: We have tests suite that is compiled, and in the app.config file I have 6-7 different connection strings to different databases. I would like to run the tests suite against every connection, and I hoped to parametrize in some way this process - so...
Hi, If I wanted to access a database in Delphi, I could add a datamodule to a project, configure it from my mainform and then access it anywhere in the application; a reference would be stored in a global variable. I know that in C# and other more modern OO languages global variables are frowned upon. So how can I access my database fr...
Hi Experts, I have a requirement where I have to select around 60 million plus records from database. Once I have all records in ResultSet then I have to formate some columns as per the client requirement(date format and number format) and then I have to write all records in a file(secondary memory). Currently I am selecting records o...
SO community I am getting started with ADO.NET and am fairly new to programming. I have had some support already from this community which has been very useful and had another question. In simple terms, I am creating a simple windows form with a combobox of employee names and a button so that when the user clicks the button the select...
I'm looking for an alternative to the rrdtool It need to be fast, reliable, able to handle large amounts of data and have a Java interface. One possibilty I'm investigating is KDB+ Any other ideas? ...
I was watching a screencast where the author said it is not good to have a primary key on a join table but didn't explain why. The join table in the example had two columns defined in a Rails migration and the author added an index to each of the columns but no primary key. Why is it not good to have a primary key in this example? c...
create_table :categories_posts, :id => false do |t| t.column :category_id, :integer, :null => false t.column :post_id, :integer, :null => false end I have a join table (as above) with columns that refer to a corresponding categories table and a posts table. I wanted to enforce a unique constraint on the composite key category_id, p...
Hi all, I am getting this error when running "./manage.py migrate app_name" While loading migration 'whatever.0001_initial': Traceback (most recent call last): File "manage.py", line 14, in <module> execute_manager(settings) ...tons of other stuff.. raise KeyError("The model '%s' from the app '%s' is not available in this migrat...
On the NerdDinner example a set of business rules are written to validate the data on a model. Things like empty strings are checked for and by calling modelObject.GetRuleViolations() you can get them all. But there's another layer of validation which is the database. For example, the datetime field is left for validation to the database...
Can't download adventure works database 2005 from codeplex. Where else can I find and download it??? I've been searching it online, I found some results but i can't download any of them. Any help is appreciated ...
I have a lightweight online shopping site based on JSP and XML, and I'm wondering what the particular weaknesses of this system are as opposed to, say, PHP and MySQL? I know JSP can use Java APIs, but I feel PHP has a more "natural" relationship with HTML and also has the benefits of being dynamically typed, and is far more widespread a...
Hi, I have a website I've created in Visual Studio 2008 and I need to take it live. How can I backup the database file to a .bak so I can hand it over to the hosting company to place on the server? ...
Update: My problem doesn't seem to be with the SQL server. I executed an update statement inside the database manually against the view and I was able to update the Bar table. I'll close this and research the OleDbDataAdapters more since I think the problem lies with them. This question applies to MS SQL Server 2000. How do I determi...
I'm designing a new revision of my Java application (using an embedded H2 database) around a redesign of the way I'll be handling my data. Here's how I have it planned: Entries table- Entry ID Entry name Properties table- Property ID Property name (Individual property) value table- Value ID Entry ID (Value columns...) (Individua...