These functions mimic their R/S-Plus counterpart
get
,
assign
,
exists
,
remove
, and
objects
,
except that they generate code that gets remotely executed
in a database engine.
A data.frame
in the case of dbReadTable
; otherwise a logical
indicating whether the operation was successful.
an PostgreSQLConnection
database connection object.
a character string specifying a table name.
a data.frame (or coercible to data.frame).
When the value
is a character string, it is assumed to be a file name containing the data to be loaded;
The implementation is INCOMPLETE and should not be used in current state.
UNTESTED;
in the case of dbReadTable
, this argument can be a string or
an index specifying the column in the DBMS table to be used as
row.names
in the output data.frame (a NULL
, ""
, or 0
specifies that no column should be used as row.names
in the output).
In the case of dbWriteTable
, this argument should be a logical
specifying whether the row.names
should be output to the
output DBMS table; if TRUE
, an extra field whose name will be
whatever the R/S-Plus identifier "row.names"
maps to the DBMS
(see make.db.names
).
a logical specifying whether to overwrite an existing table
or not. Its default is FALSE
.
a logical specifying whether to append to an existing table
in the DBMS. Its default is FALSE
.
dbWriteTable
accepts a logical allow.keywords
to allow or prevent PostgreSQL reserved identifiers to be used as
column names. By default it is FALSE
.
optional arguments.
When dbWriteTable
is used to import data from a file,
you may optionally specify header=
, row.names=
,
col.names=
, sep=
, eol=
, field.types=
,
skip=
, and quote=
. NOT FULLY IMPLEMENTED YET.
header
is a logical indicating whether the first data line
(but see skip
) has a header or not. If missing, it value
is determined following read.table
convention,
namely, it is set to TRUE if and only if the first row has one
fewer field that the number of columns.
row.names
is a logical to specify whether the first column
is a set of row names. If missing its default follows the
read.table
convention.
col.names
a character vector with column names; column names are quoted to work as SQL identifiers.
Thus, the column names are case sensitive and make.db.names
will NOT be used here.
sep=
specifies the field separator, and its default is ','
.
eol=
specifies the end-of-line delimiter, and its default is
'\n'
.
skip
specifies number of lines to skip before reading the data,
and it defaults to 0.
field.types
is a list of named field SQL types where
names(field.types)
provide the new table's column names
(if missing, field types are inferred using dbDataType
).
See the Database Interface definition document
DBI.pdf
in the base directory of this package
or https://cran.r-project.org/package=DBI.
PostgreSQL
,
isSQLKeyword
,
dbDriver
,
dbConnect
,
dbSendQuery
,
dbGetQuery
,
fetch
,
dbCommit
,
dbGetInfo
,
dbListTables
,
dbReadTable
.