Create a creel database or file connection

creel_connect() creates a validated creel_connection S3 object that fetch_*() functions dispatch on. Two backends are supported:

• DBI backend: pass any DBIConnection object (e.g., from DBI::dbConnect() with the odbc or duckdb driver).

• CSV backend: pass a named list with keys interviews, counts, catch, harvest_lengths, release_lengths pointing to CSV file paths. File existence is checked immediately at connection creation.

Both backends load data. A DBI connection reads each table by the name the schema gives it (interviews_table, counts_table, catch_table, and harvest_lengths_table / release_lengths_table, which fall back to lengths_table); a table with no name in the schema cannot be fetched.

A table name may be a string or a DBI::Id(). Use Id() for a schema-qualified table — DBI::Id(schema = "dbo", table = "vwInterviews") — because the string "dbo.vwInterviews" is treated as one literal name and will not be found.

Connections are read-only

Nothing in this package writes. A connection only ever reads: no table is created, altered, dropped or written to, no row is inserted or updated, and no file is written — including the CSV files a connection reads. Pointing a connection at a production database or an agency's live export cannot modify it.

Usage

creel_connect(con, schema)

Arguments

con

A DBIConnection object (DBI backend) or a named list of CSV file paths (CSV backend). For the CSV backend the list must contain keys: interviews, counts, catch, harvest_lengths, release_lengths.

schema

A creel_schema object created by tidycreel::creel_schema().

Value

A creel_connection S3 object.

Examples

if (FALSE) { # \dontrun{
schema <- tidycreel::creel_schema(
  survey_type = "instantaneous",
  interviews_table = "interviews",
  counts_table = "counts"
)
paths <- list(
  interviews      = "data/interviews.csv",
  counts          = "data/counts.csv",
  catch           = "data/catch.csv",
  harvest_lengths = "data/harvest_lengths.csv",
  release_lengths = "data/release_lengths.csv"
)
conn <- creel_connect(paths, schema)
} # }