Normalize a primary-key specification

Normalize and validate a primary-key (pk) specification. The canonical representation is a list with element keys containing a character vector of column names. When x (a data.frame) is provided and validate = TRUE the function will check that the columns exist (and optionally that they uniquely identify rows).

Usage

st_pk(x = NULL, keys, validate = TRUE, check_unique = FALSE)

Arguments

x

Optional data.frame to validate the keys against. If NULL, only the keys vector is normalized.

keys

Character vector of column names comprising the primary key.

validate

Logical; when TRUE validate that columns exist (and uniqueness if check_unique is TRUE).

check_unique

Logical; when TRUE assert that keys uniquely identify rows in x (only checked when x is provided).

Value

A list with element keys containing the canonical character vector.