# Introduction

The goal of dcmodifydb is to apply modification rules specified with dcmodify on a database table, allowing for documented, reproducable data cleaning adjustments in a database.

This vignette describes the supported syntax that can be used with dcmodify and dcmodifydb.

For common error scenario’s see vignette("scenarios", package="dcmodifydb")

# Syntax

## if rule

m <- modifier( if (age < 12) income = 0)

The following statements are equivalent. It is wise to choose a syntax that is familiar to the persons specifying the correction rules.

if (age < 12) income = 0  # R noobs
if (age < 12) income <- 0 # a bit more R-y
income[age < 12] <- 0     # very R-y

### else

Each if rule may be followed with an else or else if

m <- modifier(if (age > 67) {retired = TRUE} else {retired = FALSE})

The following statements are equivalent. It is wise to choose a syntax that is familiar to the persons specifying the correction rules.

if (age > 67) {retired = TRUE} else {retired = FALSE} # R noobs
if (age > 67) {retired <- TRUE} else {retired <- FALSE} # R-y
retired <- if (age > 67) TRUE else FALSE # very R-y
retired <- age > 67 # very R-y

### multiple assignments

m <- modifier(
if (age > 67) {
retired = TRUE
salary = 0
}
)