RPostgres: postgres-transactions – R documentation

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postgres-transactions

Transaction management.

Description

dbBegin() starts a transaction. dbCommit() and dbRollback() end the transaction by either committing or rolling back the changes.

Usage

## S4 method for signature 'PqConnection'
dbBegin(conn, ...)

## S4 method for signature 'PqConnection'
dbCommit(conn, ...)

## S4 method for signature 'PqConnection'
dbRollback(conn, ...)

Arguments

`conn`	a PqConnection object, produced by `DBI::dbConnect()`
`...`	Unused, for extensibility.

Value

A boolean, indicating success or failure.

Examples

# For running the examples on systems without PostgreSQL connection:
run <- postgresHasDefault()

library(DBI)
if (run) con <- dbConnect(RPostgres::Postgres())
if (run) dbWriteTable(con, "USarrests", datasets::USArrests, temporary = TRUE)
if (run) dbGetQuery(con, 'SELECT count(*) from "USarrests"')

if (run) dbBegin(con)
if (run) dbExecute(con, 'DELETE from "USarrests" WHERE "Murder" > 1')
if (run) dbGetQuery(con, 'SELECT count(*) from "USarrests"')
if (run) dbRollback(con)

# Rolling back changes leads to original count
if (run) dbGetQuery(con, 'SELECT count(*) from "USarrests"')

if (run) dbRemoveTable(con, "USarrests")
if (run) dbDisconnect(con)

RPostgres

'Rcpp' Interface to 'PostgreSQL'

v1.3.2

GPL-3

Authors

Hadley Wickham [aut], Jeroen Ooms [aut], Kirill Müller [aut, cre] (<https://orcid.org/0000-0002-1416-3412>), RStudio [cph], R Consortium [fnd], Tomoaki Nishiyama [ctb] (Code for encoding vectors into strings derived from RPostgreSQL)

Initial release

2021-04-12