| Title: | A Linear Model to 'SQL' Compiler |
| Version: | 1.0.0.0 |
| Description: | This is a cross-platform linear model to 'SQL' compiler. It generates 'SQL' from linear and generalized linear models. Its interface consists of a single function, modelc(), which takes the output of lm() or glm() functions (or any object which has the same signature) and outputs a 'SQL' character vector representing the predictions on the scale of the response variable as described in Dunn & Smith (2018) <doi:10.1007/978-1-4419-0118-7> and originating in Nelder & Wedderburn (1972) <doi:10.2307/2344614>. The resultant 'SQL' can be included in a 'SELECT' statement and returns output similar to that of the glm.predict() or lm.predict() predictions, assuming numeric types are represented in the database using sufficient precision. Currently log and identity link functions are supported. |
| License: | MIT + file LICENSE |
| URL: | https://github.com/sparkfish/modelc |
| BugReports: | https://github.com/sparkfish/modelc/issues |
| Encoding: | UTF-8 |
| LazyData: | true |
| Suggests: | testthat (≥ 2.1.0) |
| RoxygenNote: | 7.1.0 |
| NeedsCompilation: | no |
| Packaged: | 2020-06-24 22:21:46 UTC; hugo |
| Author: | Sparkfish Analytics [cph], Hugo Saavedra [aut, cre] |
| Maintainer: | Hugo Saavedra <analytics+hugo@sparkfish.com> |
| Repository: | CRAN |
| Date/Publication: | 2020-06-28 10:00:05 UTC |
Wrap the model SQL in the appropriate link function inverse to return scaled predictions
Description
Wrap the model SQL in the appropriate link function inverse to return scaled predictions
Usage
apply_linkinverse(model, sql)
Arguments
model |
A list with the same signature as the output of |
sql |
A character string representing the SQL to be wrapped in the link inverse |
Value
A character string representing a SQL model formula
Get SQL representing a continuous term in the model with no interactions
Description
Get SQL representing a continuous term in the model with no interactions
Usage
build_additive_term(model, additive_term, first = FALSE)
Arguments
model |
A list with the same signature as the output of |
additive_term |
A parameter name. |
first |
A logical flag signaling whether the term is the first term in the formula |
Value
A SQL character string representing an additive term
Build SQL CASE statements representing the factors in the model
Description
Build SQL CASE statements representing the factors in the model
Usage
build_factor_case_statements(model, first = FALSE)
Arguments
model |
A list with the same signature as the output of |
first |
A logical flag signaling whether the term is the first term in the formula |
Value
A character string representing a SQL CASE statement
Build a SQL interaction term
Description
Build a SQL interaction term
Usage
build_interaction_term(model, interaction_term, first = FALSE)
Arguments
model |
A list with the same signature as the output of |
interaction_term |
The raw interaction term (a character string) from the R model |
first |
A logical flag signaling whether the term is the first term in the formula |
Value
A character string representing a SQL interaction term
Get SQL representing the intercept term given the R model and parameter name
Description
Get SQL representing the intercept term given the R model and parameter name
Usage
build_intercept(model, parameter, first = FALSE)
Arguments
model |
A list with the same signature as the output of |
parameter |
A parameter name. |
first |
A logical flag signaling whether the term is the first term in the formula |
Value
A SQL character string representing the intercept term in the model
Build a SQL product
Description
Build a SQL product
Usage
build_product(lhs, rhs)
Arguments
lhs |
A character string representing the left hand side of the multiplication |
rhs |
A character string representing the right hand side of the multiplication |
Value
A character string representing a valid SQL product term
Extract the level from the factor name
Description
Extract the level from the factor name
Usage
extract_level(parameter, factor)
Arguments
parameter |
A parameter name |
factor |
A factor term |
Value
A SQL string literal representing the factor level
Extract the coefficient of a model parameter
Description
Extract the coefficient of a model parameter
Usage
extract_parameter_coefficient(model, parameter)
Arguments
model |
A list with the same signature as the output of |
parameter |
A character string corresponding to a model predictor |
Value
A double corresponding to the coefficient, or 0 if the coefficient is missing
Extract parameters from a linear model
Description
Extract parameters from a linear model
Usage
extract_parameters(model)
Arguments
model |
A list with the same signature as the output of |
Value
A character vector of terms from a linear model
Extract the factor name from an R model
Description
Extract the factor name from an R model
Usage
get_factor_name(parameter, model)
Arguments
parameter |
A parameter name. |
model |
A list with the same signature as the output of |
Value
A character string representing the factor name
Check if an R model contains a coefficient
Description
Check if an R model contains a coefficient
Usage
has_parameter(model, parameter)
Arguments
model |
A list with the same signature as the output of |
parameter |
A parameter name |
Value
A logical representing whether a coefficient is present in the model
Detect if the given model term is a factor
Description
Detect if the given model term is a factor
Usage
is_factor(parameter, model)
Arguments
parameter |
A parameter name. |
model |
A list with the same signature as the output of |
Value
A logical representing whether or not the term is a factor
Detect if the given model term is an interaction
Description
Detect if the given model term is an interaction
Usage
is_interaction(parameter)
Arguments
parameter |
A parameter name. |
Value
A logical representing whether or not the term is an interaction
Check if the given parameter is the intercept
Description
Check if the given parameter is the intercept
Usage
is_intercept(parameter)
Arguments
parameter |
A parameter name. |
Value
A logical representing whether the given parameter is the intercept
Compile an R model to a valid TSQL formula
Description
Compile an R model to a valid TSQL formula
Usage
modelc(model, modify_scipen = TRUE)
Arguments
model |
A list with the same signature as the output of |
modify_scipen |
A boolean indicating whether to modify the "scipen" option to avoid generating invalid SQL |
Value
A character string representing a SQL model formula
Examples
a <- 1:10
b <- 2*1:10
c <- as.factor(a)
df <- data.frame(a, b, c)
formula = b ~ a + c
# A vanilla linear model
linear_model <- lm(formula, data = df)
modelc::modelc(linear_model)
# A generalized linear model with gamma family distribution and log link function
gamma_loglink_model <- glm(formula, data = df, family=Gamma(link="log"))
modelc::modelc(gamma_loglink_model)
# A generalized linear model with gamma family distribution and identity link function
gamma_idlink_model <- glm(formula, data = df, family=Gamma(link="identity"))
modelc::modelc(gamma_idlink_model)