Define a link between a fact table and a dimension table

Creates a link descriptor that specifies how to join a dimension table to a fact table via one or more key columns.

Usage

link(key, node)

Arguments

key

A character vector or named character vector specifying join keys. Unnamed: same column name in both tables. Named: c("fact_col" = "dim_col").

node

A vectra_node object (the dimension table). Must be file-backed (created via tbl(), tbl_csv(), or tbl_sqlite()).

Value

A vectra_link object.

Examples

# \donttest{
f_obs <- tempfile(fileext = ".vtr")
f_sp  <- tempfile(fileext = ".vtr")
write_vtr(data.frame(sp_id = 1:3, value = c(10, 20, 30)), f_obs)
write_vtr(data.frame(sp_id = 1:3, name = c("A", "B", "C")), f_sp)
lnk <- link("sp_id", tbl(f_sp))
unlink(c(f_obs, f_sp))
# }