subset-methods: Extract a subset of a table or view

In greenplum-db/GreenplumR: A Fast, Easy-to-Use Tool for Manipulating Tables in Databases

Extract a subset of a table or view

Description

This function extracts a subset of a db.obj which could either be a db.table or db.view object.

Usage

## S4 method for signature 'db.obj'
subset(x, subset, select)

Arguments

x	A db.obj (either db.table or db.view) object from which to extract element(s).
subset, select	Indices specifying elements to extract or replace. Indices are ‘numeric’ or ‘character’ vectors or empty (missing) or ‘NULL’. Numeric values are coerced to integer as by ‘as.integer’ (and hence truncated towards zero).

Value

A db.Rquery object is returned which is a SQL query to extract the requested subset.

Author(s)

Author: Predictive Analytics Team at Pivotal Inc.

Maintainer: Frank McQuillan, Pivotal Inc. [e-mail]

See Also

[-methods Operator to extract elements

Examples

## Not run: 


## set up the database connection
## Assume that .port is port number and .dbname is the database name
cid <- db.connect(port = .port, dbname = .dbname, verbose = FALSE)

x <- as.db.data.frame(abalone, conn.id = cid, verbose = FALSE)
lk(x, 10)

lk(x[1:3])
lk(subset(x, 1:3))

db.disconnect(cid, verbose = FALSE)

## End(Not run)

greenplum-db/GreenplumR documentation built on Sept. 2, 2023, 8:09 a.m.