dbWriteTableArrow | R Documentation |
Writes, overwrites or appends an Arrow object to a database table.
\Sexpr[results=rd,stage=render]{DBI:::methods_as_rd("dbWriteTableArrow")}dbWriteTableArrow(conn, name, value, ...)
conn |
A DBIConnection object, as returned by
|
name |
The table name, passed on to
|
value |
An nanoarray stream, or an object coercible to a nanoarray stream with
|
... |
Other parameters passed on to methods. |
This function expects an Arrow object.
Convert a data frame to an Arrow object with nanoarrow::as_nanoarrow_array_stream()
or
use dbWriteTable()
to write a data frame.
This function is useful if you want to create and load a table at the same time.
Use dbAppendTableArrow()
for appending data to an existing
table, dbCreateTableArrow()
for creating a table and specifying field types,
and dbRemoveTable()
for overwriting tables.
dbWriteTableArrow()
returns TRUE
, invisibly.
If the table exists, and both append
and overwrite
arguments are unset,
or append = TRUE
and the data frame with the new data has different
column names,
an error is raised; the remote table remains unchanged.
An error is raised when calling this method for a closed
or invalid connection.
An error is also raised
if name
cannot be processed with dbQuoteIdentifier()
or
if this results in a non-scalar.
Invalid values for the additional arguments
overwrite
, append
, and temporary
(non-scalars,
unsupported data types,
NA
,
incompatible values,
incompatible columns)
also raise an error.
The following arguments are not part of the dbWriteTableArrow()
generic
(to improve compatibility across backends)
but are part of the DBI specification:
overwrite
(default: FALSE
)
append
(default: FALSE
)
temporary
(default: FALSE
)
They must be provided as named arguments. See the "Specification" and "Value" sections for details on their usage.
The name
argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbWriteTableArrow()
will do the quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to dbQuoteIdentifier()
: no more quoting is done
The value
argument must be a data frame
with a subset of the columns of the existing table if append = TRUE
.
The order of the columns does not matter with append = TRUE
.
If the overwrite
argument is TRUE
, an existing table of the same name
will be overwritten.
This argument doesn't change behavior if the table does not exist yet.
If the append
argument is TRUE
, the rows in an existing table are
preserved, and the new data are appended.
If the table doesn't exist yet, it is created.
If the temporary
argument is TRUE
, the table is not available in a
second connection and is gone after reconnecting.
Not all backends support this argument.
A regular, non-temporary table is visible in a second connection,
in a pre-existing connection,
and after reconnecting to the database.
SQL keywords can be used freely in table names, column names, and data. Quotes, commas, spaces, and other special characters such as newlines and tabs, can also be used in the data, and, if the database supports non-syntactic identifiers, also for table names and column names.
The following data types must be supported at least,
and be read identically with dbReadTable()
:
integer
numeric
(the behavior for Inf
and NaN
is not specified)
logical
NA
as NULL
64-bit values (using "bigint"
as field type); the result can be
converted to a numeric, which may lose precision,
converted a character vector, which gives the full decimal representation
written to another table and read again unchanged
character (in both UTF-8 and native encodings), supporting empty strings before and after a non-empty string
factor (possibly returned as character)
objects of type blob::blob (if supported by the database)
date
(if supported by the database;
returned as Date
),
also for dates prior to 1970 or 1900 or after 2038
time
(if supported by the database;
returned as objects that inherit from difftime
)
timestamp
(if supported by the database;
returned as POSIXct
respecting the time zone but not necessarily preserving the
input time zone),
also for timestamps prior to 1970 or 1900 or after 2038
respecting the time zone but not necessarily preserving the
input time zone)
Mixing column types in the same table is supported.
Other DBIConnection generics:
DBIConnection-class
,
dbAppendTable()
,
dbAppendTableArrow()
,
dbCreateTable()
,
dbCreateTableArrow()
,
dbDataType()
,
dbDisconnect()
,
dbExecute()
,
dbExistsTable()
,
dbGetException()
,
dbGetInfo()
,
dbGetQuery()
,
dbGetQueryArrow()
,
dbIsReadOnly()
,
dbIsValid()
,
dbListFields()
,
dbListObjects()
,
dbListResults()
,
dbListTables()
,
dbQuoteIdentifier()
,
dbReadTable()
,
dbReadTableArrow()
,
dbRemoveTable()
,
dbSendQuery()
,
dbSendQueryArrow()
,
dbSendStatement()
,
dbUnquoteIdentifier()
,
dbWriteTable()
con <- dbConnect(RSQLite::SQLite(), ":memory:")
dbWriteTableArrow(con, "mtcars", nanoarrow::as_nanoarrow_array_stream(mtcars[1:5, ]))
dbReadTable(con, "mtcars")
dbDisconnect(con)
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