values,tbl_validation-method: Retrieve the result of a validation/confrontation

Description

Retrieve the result of a validation/confrontation.

Usage

# S4 method for tbl_validation
values(
  x,
  simplify = type == "matrix",
  type = c("tbl", "matrix", "list", "data.frame"),
  ...
)

Arguments

tbl_validation(), result of a confront() of tbl with a rule set.

simplify

only use when type = "list" see validate::values

type

whether to return a list/matrix or to return a query on the database.

...

not used

Value

depending on type the result is different, see details

Details

Since the validation is done on a database, there are multiple options for storing the result of the validation. The results show per record whether they are valid according to the validation rules supplied.

Use compute (see confront.tbl_sql()) to store the result in the database
Use sparse to only calculate "fails" and "missings"

Default type "tbl" is that everything is "lazy", so the query and/or storage has to be done explicitly by the user. The other types execute the query and retrieve the result into R. When this creates memory problems, the tbl option is to be preferred.

Results for type:

tbl: a dbplyr::tbl_dbi object, pointing to the database
matrix: a R matrix, similar to validate::values().
list: a R list, similar to validate::values().
data.frame: the result of tbl stored in a data.frame.

Examples

Run this code

# NOT RUN {
# create a table in a database
income <- data.frame(id = letters[1:2], age=c(12,35), salary = c(1000,NA))
con <- dbplyr::src_memdb()
tbl_income <- dplyr::copy_to(con, income, overwrite=TRUE)
print(tbl_income)

# Let's define a rule set and confront the table with it:
rules <- validator( is_adult   = age >= 18
                  , has_income = salary > 0
                  , mean_age   = mean(age,na.rm=TRUE) > 20
                  )

# and confront!
cf <- confront(tbl_income, rules)
print(cf)
summary(cf)

# Values (i.e. validations on the table) can be retrieved like in `validate` 
# with`type="matrix"` (simplify = TRUE)
values(cf, type = "matrix")

# But often this seems more handy:
values(cf, type = "tbl")

# We can see the sql code by using `show_query`:
show_query(cf)

# identical
show_query(values(cf, type = "tbl"))

# adding a key often is handy in a database
cf <- confront(tbl_income, rules, key = "id")
print(cf)
values(cf, type="tbl")

# sparse results in db
cf_sparse <- confront(tbl_income, rules, sparse=TRUE)
values(cf_sparse, type="tbl")
# }