postgresqlSupport: Support Functions

Description

These functions are the workhorse behind the RPostgreSQL package, but users need not invoke these directly. For details see PostgreSQL.

Usage

## PostgreSQLDriver-related
   postgresqlInitDriver(max.con=16, fetch.default.rec = 500, force.reload=FALSE)
   postgresqlDriverInfo(obj, what, ...)
   postgresqlDescribeDriver(obj, verbose = FALSE, ...)
   postgresqlCloseDriver(drv, ...)
   ## PostgreSQLConnection-related
   postgresqlNewConnection(drv,user,password,host,dbname,port,tty,options)
   postgresqlCloneConnection(con, ...)
   postgresqlConnectionInfo(obj, what, ...)
   postgresqlDescribeConnection(obj, verbose = FALSE, ...)
   postgresqlCloseConnection(con, ...)
   ## PostgreSQLResult-related
   postgresqlExecStatement(con, statement)
   postgresqlFetch(res, n=0, ...)
   postgresqlQuickSQL(con, statement)
   postgresqlResultInfo(obj, what, ...)
   postgresqlDescribeResult(obj, verbose = FALSE, ...)
   postgresqlCloseResult(res, ...)
   postgresqlDescribeFields(res, ...)
   ## data mappings, convenience functions, and extensions
   postgresqlDataType(obj, ...)
   postgresqlReadTable(con, name, row.names = "row_names", check.names = TRUE, ...)
   postgresqlWriteTable(con, name, value, field.types, row.names = TRUE,
      overwrite=FALSE, append=FALSE, ..., allow.keywords = FALSE)
   postgresqlImportFile(con, name, value, field.types, overwrite=FALSE,
      append=FALSE, header, row.names, nrows=50, sep=",", eol="
", 
      skip = 0, quote='"', ...)
   ## Transaction Management
   postgresqlTransactionStatement(con, statement)

Arguments

max.con

positive integer specifying maximum number of open connections. The current default of 10 is hardcoded in the C code.

fetch.default.rec

default number of rows to fetch (move to R/S-Plus). This default is used in postgresqlFetch. The default is 500.

force.reload

logical indicating whether to re-initialize the driver. This may be useful if you want to change the defaults (e.g., fetch.default.rec). Note that the driver is a singleton (subsequent inits just returned the previously initialized

obj

any of the PostgreSQL DBI objects (e.g., PostgreSQLConnection, PostgreSQLResult).

what

character vector of metadata to extract, e.g., "version", "statement", "isSelect".

verbose

logical controlling how much information to display. Defaults to FALSE.

drv

an PostgreSQLDriver object as produced by postgresqlInitDriver.

con

an PostgreSQLConnection object as produced by postgresqlNewConnection and postgresqlCloneConnection.

res

an PostgreSQLResult object as produced by by postgresqlExecStatement.

user

a character string with the PostgreSQL's user name.

password

character string with the PostgreSQL's password.

dbname

character string with the PostgreSQL database name.

host

character string with the name (or IP address) of the machine hosting the database. Default is "", which is interpreted as localhost by the PostgreSQL's API.

port

(optional) positive integer specifying the TCP port number that the PostgreSQL server is listening to. Consult the PostgreSQL documentation for details.

tty

Ignored (formerly, this specified where to send server debug output)

options

Command-line options to be sent to the server

force

logical indicating whether to close a connection that has open result sets. The default is FALSE.

statement

character string holding one (and only one) SQL statement.

number of rows to fetch from the given result set. A value of -1 indicates to retrieve all the rows. The default of 0 specifies to extract whatever the fetch.default.rec was specified during driver initialization postgresqlIni

name

character vector of names (table names, fields, keywords).

value

a data.frame.

field.types

a list specifying the mapping from R/S-Plus fields in the data.frame value to SQL data types. The default is sapply(value,SQLDataType), see PostgreSQLSQLType.

header

logical, does the input file have a header line? Default is the same heuristic used by read.table, i.e., TRUE if the first line has one fewer column that the second line.

row.names

a logical specifying whether to prepend the value data.frame row names or not. The default is TRUE.

check.names

a logical specifying whether to convert DBMS field names into legal S names. Default is TRUE.

overwrite

logical indicating whether to replace the table name with the contents of the data.frame value. The defauls is FALSE.

append

logical indicating whether to append value to the existing table name.

nrows

number of lines to rows to import using read.table from the input file to create the proper table definition. Default is 50.

sep

field separator character.

eol

end-of-line separator.

skip

number of lines to skip before reading data in the input file.

quote

the quote character used in the input file (defaults to ".

allow.keywords

logical indicating whether column names that happen to be PostgreSQL keywords be used as column names in the resulting relation (table) being written. Defaults to FALSE, forcing postgresqlWriteTable to modify column nam

...

placeholder for future use.

Value

postgresqlInitDriver returns an PostgreSQLDriver object.
postgresqlDriverInfo returns a list of name-value metadata pairs.
postgresqlDescribeDriver returns NULL (displays the object's metadata).
postgresqlCloseDriver returns a logical indicating whether the operation succeeded or not.
postgresqlNewConnection returns an PostgreSQLConnection object.
postgresqlCloneConnection returns an PostgreSQLConnection object.
postgresqlConnectionInforeturns a list of name-value metadata pairs.
postgresqlDescribeConnection returns NULL (displays the object's metadata).
postgresqlCloseConnection returns a logical indicating whether the operation succeeded or not.
postgresqlExecStatement returns an PostgreSQLResult object.
postgresqlFetch returns a data.frame.
postgresqlQuickSQL returns either a data.frame if the statement is a select-like or NULL otherwise.
postgresqlDescribeResult returns NULL (displays the object's metadata). postgresqlCloseResult returns a logical indicating whether the operation succeeded or not. postgresqlDescribeFields returns a data.frame with one row per field with columns name, Sclass, type, len, precision, scale, and nullOK which fully describe each field in a result set. Except for Sclass (which shows the mapping of the field type into an R/S-Plus class) all the information pertains to PostgreSQL's data storage attributes.
postgresqlReadTable returns a data.frame with the contents of the DBMS table. postgresqlWriteTable returns a logical indicating whether the operation succeeded or not. postgresqlDataType retuns a character string with the closest postgresqlResultInfo returns a list of name-value metadata pairs.
postgresqlTransactionStatement returns a logical indicating whether the operation succeeded or not.

Constants

.PostgreSQLPkgName (currently "RPostgreSQL"), .PostgreSQLPkgVersion (the R package version), .PostgreSQLPkgRCS (the RCS revision), .PostgreSQL.NA.string (character that PostgreSQL uses to denote NULL on input), .PostgreSQLSQLKeywords (a lot!) .conflicts.OK.