The ore.groupApply function invokes an R script with an ore.frame as the input data. The ore.groupApply function passes the ore.frame to the user-defined input function as the first argument to that function. The INDEX argument to the ore.groupApply function specifies the name of a column of the ore.frame by which Oracle Database partitions the rows for processing by the user-defined R function. The ore.groupApply function can use data-parallel execution, in which one or more R engines perform the same R function, or task, on different partitions of data.
The syntax of the ore.groupApply function is the following:
ore.groupApply(X, INDEX, FUN, ..., FUN.VALUE = NULL, FUN.NAME = NULL, FUN.OWNER = NULL,
parallel = getOption("ore.parallel", NULL))
The ore.groupApply function returns an ore.list object or an ore.frame object.
Examples of the use of the ore.groupApply function are in the following topics:
See Also:
"Arguments for Functions that Run Scripts" for descriptions of the arguments to function ore.groupApply
"Installing a Third-Party Package for Use in Embedded R Execution"
Example 6-13 uses the C50 package, which has functions that build decision tree and rule-based models. The package also provides training and testing data sets. Example 6-13 builds C5.0 models on the churnTrain training data set from the churn data set of the C50 package, with the goal of building one churn model on the data for each state. The example does the following:
Loads the C50 package and then the churn data set.
Uses the ore.create function to create the CHURN_TRAIN database table and its proxy ore.frame object from churnTrain, a data.frame object.
Specifies CHURN_TRAIN, the proxy ore.frame object, as the first argument to the ore.groupApply function and specifies the state column as the INDEX argument. The ore.groupApply function partitions the data on the state column and invokes the user-defined function on each partition.
Creates the variable modList, which gets the ore.list object returned by the ore.groupApply function. The ore.list object contains the results from the execution of the user-defined function on each partition of the data. In this case, it is one C5.0 model per state, with each model stored as an ore.object object.
Specifies the user-defined function. The first argument of the user-defined function receives one partition of the data, which in this case is all of the data associated with a single state.
The user-defined function does the following:
Loads the C50 package so that it is available to the function when it executes in an R engine in the database.
Deletes the state column from the data.frame so that the column is not included in the model.
Converts the columns to factors because, although the ore.frame defined factors, when they are loaded to the user-defined function, factors appear as character vectors.
Builds a model for a state and returns it.
Uses the ore.pull function to retrieve the model from the database as the mod.MA variable and then invokes the summary function on it. The class of mod.MA is C5.0.
Example 6-13 Using the ore.groupApply Function
library(C50)
data("churn")
ore.create(churnTrain, "CHURN_TRAIN")
modList <- ore.groupApply(
CHURN_TRAIN,
INDEX=CHURN_TRAIN$state,
function(dat) {
library(C50)
dat$state <- NULL
dat$churn <- as.factor(dat$churn)
dat$area_code <- as.factor(dat$area_code)
dat$international_plan <- as.factor(dat$international_plan)
dat$voice_mail_plan <- as.factor(dat$voice_mail_plan)
C5.0(churn ~ ., data = dat, rules = TRUE)
});
mod.MA <- ore.pull(modList$MA)
summary(mod.MA)
Listing for Example 6-13
R> library(C50)
R> data(churn)
R>
R> ore.create(churnTrain, "CHURN_TRAIN")
R>
R> modList <- ore.groupApply(
+ CHURN_TRAIN,
+ INDEX=CHURN_TRAIN$state,
+ function(dat) {
+ library(C50)
+ dat$state <- NULL
+ dat$churn <- as.factor(dat$churn)
+ dat$area_code <- as.factor(dat$area_code)
+ dat$international_plan <- as.factor(dat$international_plan)
+ dat$voice_mail_plan <- as.factor(dat$voice_mail_plan)
+ C5.0(churn ~ ., data = dat, rules = TRUE)
+ });
R> mod.MA <- ore.pull(modList$MA)
R> summary(mod.MA)
Call:
C5.0.formula(formula = churn ~ ., data = dat, rules = TRUE)
C5.0 [Release 2.07 GPL Edition] Thu Feb 13 15:09:10 2014
-------------------------------
Class specified by attribute `outcome'
Read 65 cases (19 attributes) from undefined.data
Rules:
Rule 1: (52/1, lift 1.2)
international_plan = no
total_day_charge <= 43.04
-> class no [0.963]
Rule 2: (5, lift 5.1)
total_day_charge > 43.04
-> class yes [0.857]
Rule 3: (6/1, lift 4.4)
area_code in {area_code_408, area_code_415}
international_plan = yes
-> class yes [0.750]
Default class: no
Evaluation on training data (65 cases):
Rules
----------------
No Errors
3 2( 3.1%) <<
(a) (b) <-classified as
---- ----
53 1 (a): class no
1 10 (b): class yes
Attribute usage:
89.23% international_plan
87.69% total_day_charge
9.23% area_code
Time: 0.0 secs
The ore.groupApply function takes a single column or multiple columns as the INDEX argument.
Example 6-14 uses data from the CHURN_TRAIN data set to build an rpart model that produces rules on the partitions of data specified, which are the voice_mail_plan and international_plan columns. The example uses the R table function to show the number of rows to expect in each partition.
The example next invokes the ore.scriptDrop function to ensure that no script by the specified name exists in the Oracle Database R script repository. It then uses the ore.scriptCreate function to define a script named my_rpartFunction and to store it in the repository. The stored script defines a function that takes a data source and a prefix to use for naming Oracle R Enterprise datastore objects. Each invocation of the function my_rpartFunction receives data from one of the partitions identified by the values in the voice_mail_plan and international_plan columns. Because the source partition columns are constants, the function sets them to NULL. It converts the character vectors to factors, builds a model to predict churn, and saves it in an appropriately named datastore. The function creates a list to return the specific partition column values, the distribution of churn values, and the model itself.
The example then loads the rpart library, sets the datastore prefix, and invokes ore.groupApply using the values from the voice_mail_plan and international_plan columns as the INDEX argument and my_rpartFunction as the value of the FUN.NAME argument to invoke the user-defined function stored in the R script repository. The ore.groupApply function uses an optional argument to pass the datastorePrefix variable to the user-defined function. It uses the optional argument ore.connect to connect to the database when executing the user-defined function. The ore.groupApply function returns an ore.list object as the variable res.
The example displays the first entry in the list returned. It then invokes the ore.load function to load the model for the case where the customer has both the voice mail plan and the international plan.
Example 6-14 Using ore.groupApply for Partitioning Data on Multiple Columns
library(C50)
data(churn)
ore.drop("CHURN_TRAIN")
ore.create(churnTrain, "CHURN_TRAIN")
table(CHURN_TRAIN$international_plan, CHURN_TRAIN$voice_mail_plan)
options(width = 80)
head(CHURN_TRAIN, 3)
ore.scriptDrop("my_rpartFunction")
ore.scriptCreate("my_rpartFunction",
function(dat, datastorePrefix) {
library(rpart)
vmp <- dat[1, "voice_mail_plan"]
ip <- dat[1, "international_plan"]
datastoreName <- paste(datastorePrefix, vmp, ip, sep = "_")
dat$voice_mail_plan <- NULL
dat$international_plan <- NULL
dat$state <- as.factor(dat$state)
dat$churn <- as.factor(dat$churn)
dat$area_code <- as.factor(dat$area_code)
mod <- rpart(churn ~ ., data = dat)
ore.save(mod, name = datastoreName, overwrite = TRUE)
list(voice_mail_plan = vmp,
international_plan = ip,
churn.table = table(dat$churn),
rpart.model = mod)
})
library(rpart)
datastorePrefix = "my.rpartModel"
res <- ore.groupApply(CHURN_TRAIN,
INDEX = CHURN_TRAIN[, c("voice_mail_plan", "international_plan")],
FUN.NAME = "my_rpartFunction",
datastorePrefix = datastorePrefix,
ore.connect = TRUE)
res[[1]]
ore.load(name=paste(datastorePrefix, "yes", "yes", sep = "_"))
mod
Listing for Example 6-14
R> library(C50)
R> data(churn)
R> ore.drop("CHURN_TRAIN")
R> ore.create(churnTrain, "CHURN_TRAIN")
R>
R> table(CHURN_TRAIN$international_plan, CHURN_TRAIN$voice_mail_plan)
no yes
no 2180 830
yes 231 92
R>
R> options(width = 80)
R> head(CHURN_TRAIN, 3)
state account_length area_code international_plan voice_mail_plan
1 KS 128 area_code_415 no yes
2 OH 107 area_code_415 no yes
3 NJ 137 area_code_415 no no
number_vmail_messages total_day_minutes total_day_calls total_day_charge
1 25 265.1 110 45.07
2 26 161.6 123 27.47
3 0 243.4 114 41.38
total_eve_minutes total_eve_calls total_eve_charge total_night_minutes
1 197.4 99 16.78 244.7
2 195.5 103 16.62 254.4
3 121.2 110 10.30 162.6
total_night_calls total_night_charge total_intl_minutes total_intl_calls
1 91 11.01 10.0 3
2 103 11.45 13.7 3
3 104 7.32 12.2 5
total_intl_charge number_customer_service_calls churn
1 2.70 1 no
2 3.70 1 no
3 3.29 0 no
Warning messages:
1: ORE object has no unique key - using random order
2: ORE object has no unique key - using random order
R>
R> ore.scriptDrop("my_rpartFunction")
R> ore.scriptCreate("my_rpartFunction",
+ function(dat, datastorePrefix) {
+ library(rpart)
+ vmp <- dat[1, "voice_mail_plan"]
+ ip <- dat[1, "international_plan"]
+ datastoreName <- paste(datastorePrefix, vmp, ip, sep = "_")
+ dat$voice_mail_plan <- NULL
+ dat$international_plan <- NULL
+ dat$state <- as.factor(dat$state)
+ dat$churn <- as.factor(dat$churn)
+ dat$area_code <- as.factor(dat$area_code)
+ mod <- rpart(churn ~ ., data = dat)
+ ore.save(mod, name = datastoreName, overwrite = TRUE)
+ list(voice_mail_plan = vmp,
+ international_plan = ip,
+ churn.table = table(dat$churn),
+ rpart.model = mod)
+ })
R>
R> library(rpart)
R> datastorePrefix = "my.rpartModel"
R>
R> res <- ore.groupApply(CHURN_TRAIN,
+ INDEX = CHURN_TRAIN[, c("voice_mail_plan", "international_plan")],
+ FUN.NAME = "my_rpartFunction",
+ datastorePrefix = datastorePrefix,
+ ore.connect = TRUE)
R> res[[1]]
$voice_mail_plan
[1] "no"
$international_plan
[1] "no"
$churn.table
no yes
1878 302
$rpart.model
n= 2180
node), split, n, loss, yval, (yprob)
* denotes terminal node
1) root 2180 302 no (0.86146789 0.13853211)
2) total_day_minutes< 263.55 2040 192 no (0.90588235 0.09411765)
4) number_customer_service_calls< 3.5 1876 108 no (0.94243070 0.05756930)
8) total_day_minutes< 223.25 1599 44 no (0.97248280 0.02751720) *
9) total_day_minutes>=223.25 277 64 no (0.76895307 0.23104693)
18) total_eve_minutes< 242.35 210 18 no (0.91428571 0.08571429) *
19) total_eve_minutes>=242.35 67 21 yes (0.31343284 0.68656716)
38) total_night_minutes< 174.2 17 4 no (0.76470588 0.23529412) *
39) total_night_minutes>=174.2 50 8 yes (0.16000000 0.84000000) *
5) number_customer_service_calls>=3.5 164 80 yes (0.48780488 0.51219512)
10) total_day_minutes>=160.2 95 22 no (0.76842105 0.23157895)
20) state=AL,AZ,CA,CO,DC,DE,FL,HI,KS,KY,MA,MD,ME,MI,NC,ND,NE,NH,NM,OK,OR,SC,TN,VA,VT,WY 56 2 no (0.96428571 0.03571429) *
21) state=AK,AR,CT,GA,IA,ID,MN,MO,NJ,NV,NY,OH,RI,TX,UT,WA,WV 39 19 yes (0.48717949 0.51282051)
42) total_day_minutes>=182.3 21 5 no (0.76190476 0.23809524) *
43) total_day_minutes< 182.3 18 3 yes (0.16666667 0.83333333) *
11) total_day_minutes< 160.2 69 7 yes (0.10144928 0.89855072) *
3) total_day_minutes>=263.55 140 30 yes (0.21428571 0.78571429)
6) total_eve_minutes< 167.3 29 7 no (0.75862069 0.24137931)
12) state=AK,AR,AZ,CO,CT,FL,HI,IN,KS,LA,MD,ND,NM,NY,OH,UT,WA,WV 21 0 no (1.00000000 0.00000000) *
13) state=IA,MA,MN,PA,SD,TX,WI 8 1 yes (0.12500000 0.87500000) *
7) total_eve_minutes>=167.3 111 8 yes (0.07207207 0.92792793) *
R> ore.load(name = paste(datastorePrefix, "yes", "yes", sep = "_"))
[1] "mod"
R> mod
n= 92
node), split, n, loss, yval, (yprob)
* denotes terminal node
1) root 92 36 no (0.60869565 0.39130435)
2) total_intl_minutes< 13.1 71 15 no (0.78873239 0.21126761)
4) total_intl_calls>=2.5 60 4 no (0.93333333 0.06666667)
8) state=AK,AR,AZ,CO,CT,DC,DE,FL,GA,HI,ID,IL,IN,KS,MD,MI,MO,MS,MT,NC,ND,NE,NH,NJ,OH,SC,SD,UT,VA,WA,WV,WY 53 0 no (1.00000000 0.00000000) *
9) state=ME,NM,VT,WI 7 3 yes (0.42857143 0.57142857) *
5) total_intl_calls< 2.5 11 0 yes (0.00000000 1.00000000) *
3) total_intl_minutes>=13.1 21 0 yes (0.00000000 1.00000000) *