dbAppendTable: Insert rows into a table

In DBI: R Database Interface

Insert rows into a table

Description

The dbAppendTable() method assumes that the table has been created beforehand, e.g. with dbCreateTable(). The default implementation calls sqlAppendTableTemplate() and then dbExecute() with the param argument. Use dbAppendTableArrow() to append data from an Arrow stream.

\Sexpr[results=rd,stage=render]{DBI:::methods_as_rd("dbAppendTable")}

Usage

dbAppendTable(conn, name, value, ..., row.names = NULL)

Arguments

conn	A DBIConnection object, as returned by dbConnect().
name	The table name, passed on to dbQuoteIdentifier(). Options are: a character string with the unquoted DBMS table name, e.g. "table_name", a call to Id() with components to the fully qualified table name, e.g. Id(schema = "my_schema", table = "table_name") a call to SQL() with the quoted and fully qualified table name given verbatim, e.g. SQL('"my_schema"."table_name"')
value	A data.frame (or coercible to data.frame).
...	Other parameters passed on to methods.
row.names	Must be NULL.

Details

Backends compliant to ANSI SQL 99 which use ⁠?⁠ as a placeholder for prepared queries don't need to override it. Backends with a different SQL syntax which use ⁠?⁠ as a placeholder for prepared queries can override sqlAppendTable(). Other backends (with different placeholders or with entirely different ways to create tables) need to override the dbAppendTable() method.

The row.names argument is not supported by this method. Process the values with sqlRownamesToColumn() before calling this method.

Value

dbAppendTable() returns a scalar numeric.

Failure modes

If the table does not exist, or the new data in values is not a data frame or 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 row.names argument (non-scalars, unsupported data types, NA) also raise an error.

Passing a value argument different to NULL to the row.names argument (in particular TRUE, NA, and a string) raises an error.

Specification

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 non-empty strings)

• factor (returned as character, with a warning)

• list of raw (if supported by the database)

• 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.

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: dbAppendTable() will do the quoting, perhaps by calling dbQuoteIdentifier(conn, x = name)

• If the result of a call to dbQuoteIdentifier(): no more quoting is done to support databases that allow non-syntactic names for their objects:

The row.names argument must be NULL, the default value. Row names are ignored.

The value argument must be a data frame with a subset of the columns of the existing table. The order of the columns does not matter.

See Also

Other DBIConnection generics: DBIConnection-class, 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(), dbWriteTableArrow()

Examples

con <- dbConnect(RSQLite::SQLite(), ":memory:")
dbCreateTable(con, "iris", iris)
dbAppendTable(con, "iris", iris)
dbReadTable(con, "iris")
dbDisconnect(con)

DBI documentation built on June 22, 2024, 9:41 a.m.