Get Parent Lineage for a Table

Reads the parents field from a table's metadata. Returns the lineage entries recorded at write time by datom_write(). For imported tables or derived tables with no recorded lineage, returns NULL.

Usage

datom_get_parents(conn, name, version = NULL)

Arguments

conn

A datom_conn object from datom_get_conn().

name

Table name.

version

Optional metadata_sha (datom version). If NULL, reads current metadata. If provided, fetches the versioned metadata snapshot from S3.

Value

List of parent entries (each with source, table, version, data_sha), or NULL if no lineage is recorded. The data_sha field is the parent's authoritative data SHA recorded via datom_parent(), and together with source and version is sufficient to select the parent's project connection and its pinned version.

See also

datom_get_lineage() for a unified interface that also exposes the transitive source_lineage field via depth = "source".

Examples

# Offline, self-contained: a bare git repo stands in for GitHub and a
# local directory for object storage.
if (requireNamespace("git2r", quietly = TRUE)) {
  tmp <- tempfile("datom-example-")
  remote <- file.path(tmp, "remote.git")
  dir.create(remote, recursive = TRUE)
  git2r::init(remote, bare = TRUE)

  store <- datom_store(
    data = datom_store_local(file.path(tmp, "storage")),
    github_pat = "example-token", # role selector; a local remote needs none
    data_repo_url = remote,
    validate = FALSE
  )
  datom_init_repo(file.path(tmp, "repo"), "example_project", store)
  conn <- datom_get_conn(file.path(tmp, "repo"), store)

  dm <- datom_example_data("dm")
  datom_write(conn, data = dm, name = "dm")
  datom_write(
    conn,
    data    = dm[dm$SEX == "F", ],
    name    = "dm_female",
    parents = list(datom_parent(conn, "dm", datom_history(conn, "dm")$version[1]))
  )
  print(datom_get_parents(conn, "dm_female"))

  unlink(tmp, recursive = TRUE)
}
#> ℹ Created store directory /tmp/Rtmpvh48Dj/datom-example-1a7617003c08/storage.
#> ✔ Initialized datom repository "example_project" at /tmp/Rtmpvh48Dj/datom-example-1a7617003c08/repo
#> ✔ Wrote "dm" (full): "b5cbba45"
#> ✔ Wrote "dm_female" (full): "612321c1"
#> [[1]]
#> [[1]]$source
#> [1] "example_project"
#> 
#> [[1]]$table
#> [1] "dm"
#> 
#> [[1]]$version
#> [1] "b5cbba4501f518d7bbe1eaf4f0c236895b12d63677b9f75b9388b715055c832e"
#> 
#> [[1]]$data_sha
#> [1] "71a93ffaa4cdc59750a5d5fbf49bb4ffcd656f00038cae2849958acae622b538"
#> 
#>