multiple-tables

I have one BIG file (>10000 lines of data) and I want write out a separate file by ID. I have 50 unique ID names and I want a separate text file for each one. Here's what Ive got so far, and I keep getting errors. My ID is actually character string which I would prefer if I can name each file after that character string it would be best. for (i in 1:car$ID) { a <- data.frame(car[,i]) carib <- car1[,(c("x","y","time","sd"))] myfile <- gsub("( )", "", paste("C:/bridge", carib, "_", i, ".txt")) write.table(a, file=myfile, sep="", row.names=F, col.names=T quote=FALSE, append=FALSE) } One approach

I'm learning ASP.NET MVC 3 and trying to create a View with a single form which is made up of multiple Models linked together by a foreign key. The end goal is to have the single form insert into all the database tables. The problem is that I cannot figure out why when I right click to create the View that the form is not auto-generated in the cshtml file. Auto-generated code helps a lot since I have many tables that link together, and many fields which I must validate and insert. If it's not possible to auto-generate the form, what is the most efficient/elegant way to get this done? Here's a

I want to drop multiple tables with ease without actually listing the table names in the drop query and the tables to be deleted have prefix say 'wp_' I've used a query very similar to Angelin's. In case you have more than a few tables, one has to increase the max length of group_concat . Otherwise the query will barf on the truncated string that group_concat returns. This is my 10 cents: -- Increase memory to avoid truncating string, adjust according to your needs SET group_concat_max_len = 1024 * 1024 * 10; -- Generate drop command and assign to variable SELECT CONCAT('DROP TABLE ',GROUP

I've got one master table, which has items stored in multiple levels, parents and childs, and there is a second table which may or may not have additional data. I need to query two levels from my master table and have a left join on my second table, but because of the ordering within my query this will not work. SELECT something FROM master as parent, master as child LEFT JOIN second as parentdata ON parent.secondary_id = parentdata.id LEFT JOIN second as childdata ON child.secondary_id = childdata.id WHERE parent.id = child.parent_id AND parent.parent_id = 'rootID' The left join only works

Are there standards or best practices yet when it comes to multi table inheritance in rails 3? So far the best article I could find was: http://mediumexposure.com/multiple-table-inheritance-active-record/ But even that needed some changes(e.g. moving the requires to an initializer instead of the old /config/environment.rb) Any better resources / standards? There's a guy in the Melbourne Ruby group I attend that's written a couple of blogs on table inheritance in rails and the comments are really helpful as well. It's not specifically Rails 3 but there's definitely some decent pointers in there

I'm new to SQL. I have a simple problem with getting the results from two different tables. I have two tables in a database. The first table has a column with an id reference, which corresponds to rows in the second table. What SELECT do I need to perform to get a result such that the ids are repalced by all of the values in the second table. To visualize the tables I am discussing: TABLE_USERS =========== id username group -- -------- ----- 1 jim A 2 alice A 3 brandon B TABLE_GROUPS ============ id groupname members -- --------- ------- A designer 134 B photographer 39 DESIRED_SELECTION =====