with_db_connection: DBMS Connections which disconnect themselves.

Description Usage Arguments Value See Also Examples

View source: R/db.R

Description

Connections to Database Management Systems which automatically disconnect. In particular connections which are created with DBI::dbConnect() and closed with DBI::dbDisconnect().

Usage

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with_db_connection(con, code)

local_db_connection(con, .local_envir = parent.frame())

Arguments

con

For with_db_connection() a named list with the connection(s) to create. For local_db_connection() the code to create a single connection, which is then returned.

code

[any]
Code to execute in the temporary environment

.local_envir

[environment]
The environment to use for scoping.

Value

[any]
The results of the evaluation of the code argument.

See Also

withr for examples

Examples

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db <- tempfile()
with_db_connection(
  list(con = DBI::dbConnect(RSQLite::SQLite(), db)), {
    DBI::dbWriteTable(con, "mtcars", mtcars)
})

head_db_table <- function(...) {
  con <- local_db_connection(DBI::dbConnect(RSQLite::SQLite(), db))
  head(DBI::dbReadTable(con, "mtcars"), ...)
}
head_db_table()
unlink(db)

jimhester/withr documentation built on Jan. 1, 2020, 12:51 p.m.