copy_to.src_sql {dbplyr}R Documentation

Copy a local data frame to a remote database

Description

This is an implementation of the dplyr copy_to() generic and it mostly a wrapper around DBI::dbWriteTable().

It is useful for copying small amounts of data to a database for examples, experiments, and joins. By default, it creates temporary tables which are only visible within the current connection to the database.

Usage

## S3 method for class 'src_sql'
copy_to(
  dest,
  df,
  name = deparse(substitute(df)),
  overwrite = FALSE,
  types = NULL,
  temporary = TRUE,
  unique_indexes = NULL,
  indexes = NULL,
  analyze = TRUE,
  ...,
  in_transaction = TRUE
)

Arguments

dest

remote data source

df

A local data frame, a tbl_sql from same source, or a tbl_sql from another source. If from another source, all data must transition through R in one pass, so it is only suitable for transferring small amounts of data.

name

name for new remote table.

overwrite

If TRUE, will overwrite an existing table with name name. If FALSE, will throw an error if name already exists.

types

a character vector giving variable types to use for the columns. See https://www.sqlite.org/datatype3.html for available types.

temporary

if TRUE, will create a temporary table that is local to this connection and will be automatically deleted when the connection expires

unique_indexes

a list of character vectors. Each element of the list will create a new unique index over the specified column(s). Duplicate rows will result in failure.

indexes

a list of character vectors. Each element of the list will create a new index.

analyze

if TRUE (the default), will automatically ANALYZE the new table so that the query optimiser has useful information.

...

other parameters passed to methods.

in_transaction

Should the table creation be wrapped in a transaction? This typically makes things faster, but you may want to suppress if the database doesn't support transactions, or you're wrapping in a transaction higher up (and your database doesn't support nested transactions.)

Value

Another tbl_lazy. Use show_query() to see the generated query, and use collect() to execute the query and return data to R.

Examples

library(dplyr, warn.conflicts = FALSE)

df <- data.frame(x = 1:5, y = letters[5:1])
db <- copy_to(src_memdb(), df)
db

df2 <- data.frame(y = c("a", "d"), fruit = c("apple", "date"))
# copy_to() is called automatically if you set copy = TRUE
# in the join functions
db %>% left_join(df2, copy = TRUE)

[Package dbplyr version 2.1.1 Index]