You can create a temporary database table, and its corresponding proxy ore.frame object, from a local R object with the ore.push function. You can create a local R object that contains a copy of data represented by an Oracle R Enterprise proxy object with the ore.pull function.
The ore.push function translates an R object into an Oracle R Enterprise object of the appropriate data type. The ore.pull function takes an ore class object and returns an R object. If the input object is an ore.list, the ore.pull function creates a data.frame and translates each the data of each database column into the appropriate R representation.
Note:
You can pull data to a local R data.frame only if the data can fit into the R session memory. Also, even if the data fits in memory but is still very large, you may not be able to perform many, or any, R functions in the client R session.
Example 2-16 demonstrates pushing an R data.frame object to the database as a temporary database table with an associated ore.frame object, iris_of, then creating another ore.frame object, iris_of_setosa, by selecting one column from iris_of, and then pulling the iris_of_setosa object into the local R session memory as a data.frame object. The example displays the class of some of the objects.
Unless you explicitly save them, the temporary database tables and their corresponding Oracle R Enterprise proxy objects that you create with the ore.push function are discarded when you quit the R session.
See Also:
"Transparency Layer Support for R Data Types and Classes" for information on data type mappings
"Saving and Managing R Objects in the Database" for information on permanently saving the Oracle R Enterprise objects in the database
The push_pull.R example script
Example 2-16 Using ore.push and ore.pull to Move Data
class(iris) # Push the iris data frame to the database. iris_of <- ore.push(iris) class(iris_of) # Display the data type of the Sepal.Length column in the data.frame. class(iris$Sepal.Length) # Display the data type of the Sepal.Length column in the ore.frame. class(iris_of$Sepal.Length) # Filter one column of the data set. iris_of_setosa <- iris_of[iris_of$Species == "setosa", ] class(iris_of_setosa) # Pull the selected column into the local R client memory. local_setosa = ore.pull(iris_of_setosa) class(local_setosa)Listing for Example 2-16
R> class(iris) [1] "data.frame" R> # Push the iris data frame to the database. R> iris_of <- ore.push(iris) R> class(iris_of) [1] "ore.frame" attr(,"package") [1] "OREbase" R> # Display the data type of the Sepal.Length column in the data.frame. R> class(iris$Sepal.Length) [1] "numeric" R> # Display the data type of the Sepal.Length column in the ore.frame. R> class(iris_of$Sepal.Length) [1] "ore.numeric" attr(,"package") [1] "OREbase" R> # Filter one column of the data set. R> iris_of_setosa <- iris_of[iris_of$Species == "setosa", ] R> class(iris_of_setosa) [1] "ore.frame" attr(,"package") [1] "OREbase" R> # Pull the selected column into the local R client memory. R> local_setosa = ore.pull(iris_of_setosa) R> class(local_setosa) [1] "data.frame"