modeldb
Fit models inside the database. modeldb
works with most databases
back-ends because it leverages dplyr
and dbplyr
for the final SQL
translation of the algorithm. It currently supports:
K-means clustering
Linear regression
Installation
Install the CRAN version with:
# install.packages("modeldb")
The development version is available using devtools
as follows:
# install.packages("remotes")
# remotes::install_github("tidymodels/modeldb")
Linear regression
An easy way to try out the package is by creating a temporary SQLite
database, and loading mtcars
to it
con <- DBI::dbConnect(RSQLite::SQLite(), path = ":memory:")
RSQLite::initExtension(con)
dplyr::copy_to(con, mtcars)
library(dplyr)
tbl(con, "mtcars") %>%
select(wt, mpg, qsec) %>%
linear_regression_db(wt)
## # A tibble: 1 x 3
## `(Intercept)` mpg qsec
## <dbl> <dbl> <dbl>
## 1 4.12 -0.156 0.125
The model output can be parsed by tidypredict
to run the predictions
in the database. Please see the Linear Regression
article to learn
more about how to use linear_regression_db()
K Means clustering
To use the simple_kmeans_db()
function, simply pipe the database back
end table to the function. This returns a list object that contains two
items:
- A sql query table with the final center assignment
- A local table with the information about the centers
km <- tbl(con, "mtcars") %>%
simple_kmeans_db(mpg, wt)
colnames(km)
## [1] "k_center" "k_mpg" "k_wt" "mpg" "cyl" "disp"
## [7] "hp" "drat" "wt" "qsec" "vs" "am"
## [13] "gear" "carb"
The SQL statement from tbl
can be extracted using dbplyr
’s
remote_query()
dbplyr::remote_query(km)
## <SQL> SELECT `RHS`.`center` AS `k_center`, `LHS`.`k_mpg` AS `k_mpg`, `LHS`.`k_wt` AS `k_wt`, `RHS`.`mpg` AS `mpg`, `RHS`.`cyl` AS `cyl`, `RHS`.`disp` AS `disp`, `RHS`.`hp` AS `hp`, `RHS`.`drat` AS `drat`, `RHS`.`wt` AS `wt`, `RHS`.`qsec` AS `qsec`, `RHS`.`vs` AS `vs`, `RHS`.`am` AS `am`, `RHS`.`gear` AS `gear`, `RHS`.`carb` AS `carb`
## FROM (SELECT `center` AS `k_center`, `mpg` AS `k_mpg`, `wt` AS `k_wt`
## FROM (SELECT `center`, AVG(`mpg`) AS `mpg`, AVG(`wt`) AS `wt`
## FROM (SELECT `mpg`, `wt`, `center`
## FROM (SELECT *
## FROM (SELECT `mpg`, `cyl`, `disp`, `hp`, `drat`, `wt`, `qsec`, `vs`, `am`, `gear`, `carb`, `center_1`, `center_2`, `center_3`, CASE
## WHEN (`center_1` >= `center_1` AND `center_1` < `center_2` AND `center_1` < `center_3`) THEN ('center_1')
## WHEN (`center_2` < `center_1` AND `center_2` >= `center_2` AND `center_2` < `center_3`) THEN ('center_2')
## WHEN (`center_3` < `center_1` AND `center_3` < `center_2` AND `center_3` >= `center_3`) THEN ('center_3')
## END AS `center`
## FROM (SELECT `mpg`, `cyl`, `disp`, `hp`, `drat`, `wt`, `qsec`, `vs`, `am`, `gear`, `carb`, SQRT(((20.6428571428571 - `mpg`) * (20.6428571428571 - `mpg`)) + ((3.07214285714286 - `wt`) * (3.07214285714286 - `wt`))) AS `center_1`, SQRT(((14.4583333333333 - `mpg`) * (14.4583333333333 - `mpg`)) + ((4.05866666666667 - `wt`) * (4.05866666666667 - `wt`))) AS `center_2`, SQRT(((30.0666666666667 - `mpg`) * (30.0666666666667 - `mpg`)) + ((1.873 - `wt`) * (1.873 - `wt`))) AS `center_3`
## FROM `mtcars`))
## WHERE (NOT(((`center`) IS NULL)))))
## GROUP BY `center`)) AS `LHS`
## RIGHT JOIN (SELECT `mpg`, `cyl`, `disp`, `hp`, `drat`, `wt`, `qsec`, `vs`, `am`, `gear`, `carb`, `center`
## FROM (SELECT `mpg`, `cyl`, `disp`, `hp`, `drat`, `wt`, `qsec`, `vs`, `am`, `gear`, `carb`, `center_1`, `center_2`, `center_3`, CASE
## WHEN (`center_1` >= `center_1` AND `center_1` < `center_2` AND `center_1` < `center_3`) THEN ('center_1')
## WHEN (`center_2` < `center_1` AND `center_2` >= `center_2` AND `center_2` < `center_3`) THEN ('center_2')
## WHEN (`center_3` < `center_1` AND `center_3` < `center_2` AND `center_3` >= `center_3`) THEN ('center_3')
## END AS `center`
## FROM (SELECT `mpg`, `cyl`, `disp`, `hp`, `drat`, `wt`, `qsec`, `vs`, `am`, `gear`, `carb`, SQRT(((20.6428571428571 - `mpg`) * (20.6428571428571 - `mpg`)) + ((3.07214285714286 - `wt`) * (3.07214285714286 - `wt`))) AS `center_1`, SQRT(((14.4583333333333 - `mpg`) * (14.4583333333333 - `mpg`)) + ((4.05866666666667 - `wt`) * (4.05866666666667 - `wt`))) AS `center_2`, SQRT(((30.0666666666667 - `mpg`) * (30.0666666666667 - `mpg`)) + ((1.873 - `wt`) * (1.873 - `wt`))) AS `center_3`
## FROM `mtcars`))
## WHERE (NOT(((`center`) IS NULL)))) AS `RHS`
## ON (`LHS`.`k_center` = `RHS`.`center`)