values-tbl_validation-method: Retrieve the result of a validation/confrontation
In validatedb: Validate Data in a Database using 'validate'

Description Usage Arguments Details Value See Also Examples

Retrieve the result of a validation/confrontation.

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

`x`	`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

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.

depending on type the result is different, see details

Other validation: confront.tbl_sql(), tbl_validation-class

# 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")