similar to: foreign key question

I''m a beginning programming using ActiveRecord outside of Rails to do conditional processing of database records. So far, I''ve been successful. However, my script loads all matching records into memory first. There are hundreds of thousands of matching records so the script quickly consumes over 500MB of RAM before any processing is done. Is there a way to avoid this preloading

Hi there ! I try to figure out how to do something like this in Rails : SELECT * FROM my_table WHERE name LIKE ''GOGONAM%'' My problem is the % and the quotes. >From now, I do like this : searched_name = params[:name]+''%'' user = MyTable.find(:all, :conditions => ["name LIKE ?", searched_name]) But is there a more gracefull way to do a LIKE

Adding a column to a table just places the column at the end, but I like to keep related columns together. Is there a way to specify where the column is added in a table with migrations? For example, in MySQL you can do: ALTER TABLE my_table ADD COLUMN new_column INT AFTER other_column I was hoping migrations would support something like this: add_column :my_table, :new_column, :integer,

Hi everyone, I have a question regarding a C function of the "stats" package in R. I tried to understand the ?loglin? basic function of the ?stats? package implemented in R. The implemented function itself runs without any problem (perhaps see sample). When I ran it line by line it stopped at the lines 23-24 of the loglin-function; (the following line): z <- .Call(C_LogLin,

Dear R-Helpers, I've looked high and low for a function that provides frequencies, proportions and cumulative proportions side-by-side. Below is the table I need. Is there a function that already does it? Thanks, Bob > # Generate some test scores > myValues <- c(70:95) > Score <- ( sample( myValues, size=1000, replace=TRUE) ) > head(Score) [1] 77 71 81 88 83 93 > >

Yes, I am a newbie. I have a data.frame (MyTable) of 1445846 rows and 15 columns with character data. And a character vector (MyVector) of 473491 elements. I want simply to get a data.frame with the count of how many times each element of MyVector appears in MyTable. I've tried a loop with : for (i in 1 : length (myvector)) sum (MyTable== i) but it crashes my computer. I've also

Hi all, when i run this script: >read.table("Angelika.txt",header=T,sep="\t") >mytable=read.table("Angelika.txt",header=T,sep="\t") >for ( dye in c("A","B","C","F","G","K","L","M")) + { + for (cond in 1:8) + { + measurement =

Hi, Anyone got any cool tricks for converting a Rails site (in this case, a typo installation) from a mysql database to a postgresql database? I''ve got it almost working -- I''m doing a SQL dump from mysql and loading it into postgres. However, mysql does booleans as a tinyint with 0 = false and 1 = true. When I try to import that into a postgres database that expects booleans

Hello, Let's assume I have a vector of integers : > myvector <- c(1, 2, 3, 2, 1, 3, 5) My purpose is to obtain the cumulative distribution of these numerical data, i.e. something like : value nb_occur. <=1 2 <=2 4 <=3 6 <=4 6 <=5 7 For this, I create a table with ; > mytable <- table(myvector) 1 2 3 5 2 2 2 1 However, table() returns an array

I feel this is a very easy thing but I've never done it before and it is getting frustrating. I have a big data.frame (1445846 rows, 15 col) that looks like this: V1 V2 V3 V4 V5 1 home sister brother chair 0 2 cat dog animal 0 0 3 girl boy 0

Hello, In my script I would like to use a loop, which sorts the dataframe according to different columns, pointed by the string variable. id col1 col2 col3 1 10 0 4 8 2 11 1 2 2 3 12 0 8 3 4 13 0 5 5 Usually the order() function can be used like this: sorted = mytable**[order(column3) , ] which results in properly sorted table: **

I have created a function to do something: i <- factor(sample(c("A", "B", "C", NA), 793, rep=T, prob=c(8, 7, 5, 1))) k <- factor(sample(c("X", "Y", "Z", NA), 793, rep=T, prob=c(12, 7, 9, 1))) mytable <- function(x){ xtb <- x btx <- x # do more with x, not relevant here cat("The table has been created,

If do something like this: dbObj = MyTable.find_by_id(5) a = dbObj.name b = dbObj.name How many times will an SQL call be made to get the value of MyTable.name for id 5? In other words, are the values for dbObj cached in the object? Is there a way of controlling that? (I can imagine that sometimes you might not want to cache them if you wanted to be sure of having the latest

I have just started with Ruby and Rails and am still greatly confuse, finding the usual tutorials not much help. What I want to do is take two numbers from my database, multiply them together and display them in a list with a comma for the thousands separator. This would be very easy to do in a spreadsheet, so I assumed it would be easy to do in Ruby on Rails but I can''t work out how. I

Hi all, I'm sure this is simple but I don't get it. I have a table mytable<-c(rep("Disagree",37),rep("Agree",64)) table(mytable) this gives me Agree Disagree 64 37 but I didn't ask for it to be in alphabetic order. How can I get it in original order? Disagree Agree 37 64 Thanks, Jeff Jeffrey. M. Miller, PhD

Dear Friends, I am seeking for any help on an error message in lme functions. I use mixed model to analyze a data with compound symmetric correlation structure. But I get an error message: "Error in corMatrix.corCompSymm(object) : NA/NaN/Inf in foreign function call (arg 1)". If I change the correlation structure to corAR1, then no error. I have no clue how to solve this problem.

Getting the basic stuff to work is trivially simple. I can connect, and, for example, get everything in any given table. What I have yet to find is how to deal with parameterized queries or how to do a simple insert (but not of a value known at the time the script is written - I ultimately want to put my script into a scheduled task, so the analysis can be repeated on updated data either daily

I've been playing around with various table tools, trying to construct a fairly simple cross-tab. It shouldn't be hard, but for some reason it turning out to be (for me). If I want to see how many men and how many women agree with a agree/disagree question (coded 1,0), I can do this: >attach(mydata) >mytable <- table(male, q1.bin) # gender and a binary response variable

I am a relatively new user to R, and I am trying to learn more about converting data in an XML document into "2-dimensional format" such as a table or array. I might eventually wish to export this data into a relational database such as SQL, and/or to work with this data within the R package. My sample XML document is located at "

Calling function "sqlFetch" in library(RODBC) and specifying a character string as 2nd argument, I get an error I don't understand: library(RODBC) channel <- odbcConnect("mydatabase.mdb", case="msaccess") sqlFetch(channel, "mytable") # this works fine tabname <- "mytable"; sqlFetch(channel, tabname) # this gives an error: # Error in