\name{dbGetComparisons}
\alias{dbGetComparisons}
%- Also NEED an '\alias' for EACH other topic documented here.
\title{Get a list of all comparisons from the database}
\description{
This function can be used to get all available information about comparisons that are stored in the database (i.e. which samples/signal channels are compared in which comparison).
}
\usage{
dbGetComparisons(con, exp.title = NULL, join.tables = c("signal_channels", "samples", "arrays", "experiments"))
}
%- maybe also 'usage' for other objects documented here.
\arguments{
  \item{con}{The connection to the database.}
  \item{exp.title}{Get the comparisons that were created within a specific micro array experiment that was saved in the database. If not submitted all comparisons will be returned. To get the information about the experiments stored in the database, call \code{\link{dbGetExperimentInfo}}.}
  \item{join.tables}{The tables with which the comparisons will be joined. In the default case (which means join to all tables) all information concerning the comparisons (which experiment, sample, array \dots was used) will be returned.}
}
\value{
The function returns a table with rows corresponding to the comparisons and columns to the attributes of the different tables (column names ending in \dQuote{red} belong to the red signal channel and column names ending in \dQuote{green} to the green respectively).
}
\note{
For further information and examples refer to the package vignette (which can be opened using \code{\link{openMadbVignette}}).
}
\author{Johannes Rainer}
\seealso{\code{\link{dbGetExperimentInfo}}, \code{\link{createJOINQuery}}}
\keyword{data}