Transfer 'REDCap' Data to a Database

Transfer REDCap data to a database in chunks to minimize memory usage.

Usage

redcap_to_db(
  conn,
  data_table_name = "data",
  log_table_name = "log",
  redcap_uri,
  token,
  raw_or_label = "raw",
  raw_or_label_headers = "raw",
  export_checkbox_label = FALSE,
  export_survey_fields = FALSE,
  export_data_access_groups = FALSE,
  blank_for_gray_form_status = FALSE,
  filter_logic = "",
  datetime_range_begin = as.POSIXct(NA),
  datetime_range_end = as.POSIXct(NA),
  fields = NULL,
  forms = NULL,
  events = NULL,
  record_id_name = "record_id",
  chunk_size = 1000,
  chunk_delay = 0.5,
  max_retries = 10,
  echo = "all",
  beep = TRUE,
  ...
)

Arguments

conn: A DBI connection object to a database.
data_table_name: Character string specifying the name of the table to create or append data to. Default is "data". Can include schema name (e.g. "schema.table").
log_table_name: Character string specifying the name of the table to store transfer logs. Default is "log". Can include schema name (e.g. "schema.log"). Set to NULL to disable logging.
redcap_uri: Character string specifying the URI (uniform resource identifier) of the REDCap server's API.
token: Character string containing the REDCap API token specific to your project. This token is used for authentication and must have export permissions.
raw_or_label: A string (either "raw" or "label") that specifies whether to export the raw coded values or the labels for the options of multiple choice fields. Default is "raw".
raw_or_label_headers: A string (either "raw" or "label") that specifies for the CSV headers whether to export the variable/field names (raw) or the field labels (label). Default is "raw".
export_checkbox_label: Logical that specifies the format of checkbox field values specifically when exporting the data as labels. If raw_or_label is "label" and export_checkbox_label is TRUE, the values will be the text displayed to the users. Otherwise, the values will be 0/1. Default is FALSE.
export_survey_fields: Logical that specifies whether to export the survey identifier field (e.g., 'redcap_survey_identifier') or survey timestamp fields. Default is FALSE.
export_data_access_groups: Logical that specifies whether or not to export the redcap_data_access_group field when data access groups are utilized in the project. Default is FALSE.
blank_for_gray_form_status: Logical that specifies whether or not to export blank values for instrument complete status fields that have a gray status icon. Default is FALSE.
filter_logic: String of logic text (e.g., [gender] = 'male') for filtering the data to be returned, where the API will only return records where the logic evaluates as TRUE. Default is an empty string.
datetime_range_begin: To return only records that have been created or modified after a given datetime, provide a POSIXct value. Default is NA (no begin time).
datetime_range_end: To return only records that have been created or modified before a given datetime, provide a POSIXct value. Default is NA (no end time).
fields: Character vector specifying which fields to export. Default is NULL (all fields).
forms: Character vector specifying which forms to export. Default is NULL (all forms).
events: Character vector specifying which events to export. Default is NULL (all events).
record_id_name: Character string specifying the field name that contains record identifiers used for chunking requests. Default is "record_id".
chunk_size: Integer specifying the number of record IDs to process per chunk. Default is 1000. Consider decreasing this for projects with many fields.
chunk_delay: Numeric value specifying the delay in seconds between chunked requests. Default is 0.5 seconds. Adjust to respect REDCap server limits.
max_retries: Integer specifying the maximum number of retry attempts for failed API connection or HTTP 504 error. Default is 10.
echo: String indicating whether to show progress and/or completion messages. Options: "all" (default), "progress", or "none".
beep: Logical indicating whether to play sound notifications when the process completes or encounters errors. Default is TRUE.
...: Additional arguments passed to the REDCap API call.

Value

Returns a list with the following components:

success: Logical if the transfer was completed with no failed processing
error_chunks: Vector of chunk numbers that failed processing
time_s: Numeric value for total seconds to transfer and optimize data

Details

This function transfers data from REDCap to any database in chunks, which helps manage memory usage when dealing with large projects. It creates two tables in the database:

data_table_name: Contains all transferred REDCap records
log_table_name: Contains timestamped logs of the transfer process

The function automatically detects existing databases and handles them in three ways:

If no table exists, starts a new transfer process
If a table exists but is incomplete, resumes from the last processed record ID
If a table exists and is complete, returns success without reprocessing

The function fetches record IDs, then processes records in chunks. If any error occurs during processing, the function will continue with remaining chunks but mark the transfer as incomplete.

Data is first set to VARCHAR/TEXT type for consistent handling across chunks. For DuckDB, data types are automatically optimized after all data is inserted:

INTEGER: Columns with only whole numbers
DOUBLE: Columns with decimal numbers
DATE: Columns with valid dates
TIMESTAMP: Columns with valid timestamps
VARCHAR/TEXT: All other columns remain as strings

Examples

if (FALSE) { # \dontrun{
# install.packages("pak")
# pak::pak(c("duckdb", "keyring", "redquack"))

library(redquack)

duckdb <- DBI::dbConnect(duckdb::duckdb(), "redcap.duckdb")

result <- redcap_to_db(
  redcap_uri = "https://redcap.example.org/api/",
  token = keyring::key_get("redcap_token"),
  conn = duckdb,
)

data <- DBI::dbGetQuery(duckdb, "SELECT * FROM data LIMIT 1000")
log <- DBI::dbGetQuery(duckdb, "SELECT * FROM log")

DBI::dbDisconnect(duckdb)
} # }

Usage

Arguments

Value

Details

See also

Examples