With ore.attach, you add an R environment for a database schema to the R search path. When you add the R environment, you have access to database tables by name through the proxy objects created by the ore.sync function without needing to specify the schema environment.
The default schema is the one specified in creating the connection and the default position in the search path is 2. You can specify the schema and the position in the ore.attach function invocation.. You can also specify whether you want the ore.attach function to indicate whether a naming conflict occurs when adding the environment. You can detach the environment for a schema from the R search path with the ore.detach function.
Example 2-12 Using ore.attach to Add an Environment for a Database Schema
This example demonstrates the use of the ore.attach function. Comments in the example explain the function invocations.
# Connected as rquser.
# Add the environment for the rquser schema to the R search path.
ore.attach()
# Create an unordered ore.frame proxy object in the SH environment for the
# specifed table.
ore.sync(schema = "SH", table = "CUSTOMERS", use.keys = FALSE)
# Add the environment for the SH schema to the search path and warn if naming
# conflicts exist.
ore.attach("SH", 3, warn.conflicts = TRUE)
# Display the number of rows and columns in the proxy object for the table.
dim(CUSTOMERS)
# Remove the environment for the SH schema from the search path.
ore.detach("SH")
# Invoke the dim function again.
dim(CUSTOMERS)
Listing for Example 2-12
R> # Connected as rquser.
R> # Add the environment for the rquser schema to the R search path.
R> ore.attach()
R> # Create an unordered ore.frame proxy object in the SH environment for the
R> # specifed table.
R> ore.sync(schema = "SH", table = "CUSTOMERS", use.keys = FALSE)
R> # Add the environment for the SH schema to the search path and warn if naming
R> # conflicts exist.
R> ore.attach("SH", 3, warn.conflicts = TRUE)
R> # Display the number of rows and columns in the proxy object for the table.
R> dim(CUSTOMERS)
[1] 630 15
R> # Remove the environment for the SH schema from the search path.
R> ore.detach("SH")
R> # Invoke the dim function again.
R> dim(CUSTOMERS)
Error: object 'CUSTOMERS' not found