GreenplumR: A Fast, Easy-to-Use Tool for Manipulating Tables in Databases

delete

R Documentation

Safely delete a `db.obj` object or a table/view in the database

Description

This function deletes a db.data.frame object together with the table/view that it points to. It deletes a db.Rquery object. It can also directly delete a table or view in the database. When applied onto some composite data objects, it deletes the data table wrapped by them.

Usage


## S4 method for signature 'db.data.frame'
delete(x, cascade = FALSE)

## S4 method for signature 'db.Rquery'
delete(x)

## S4 method for signature 'character'
delete(x, conn.id = 1, is.temp = FALSE, cascade =
FALSE)

## S4 method for signature 'bagging.model'
delete(x)

Arguments

`x`	The signature of the method. A `db.data.frame` object, which points to a table or view in the database; Or a `db.Rquery` object, which represents some operations on an existing `db.data.frame` object; Or a string, the table/view name to delete in the database. In the this case, the result model tables wrapped by `model`, `residuals` and `statistics` will be deleted.
`conn.id`	An integer, default is 1. The connection ID to the database.
`is.temp`	A logical, default is `FALSE`. Whether the table/view is temporary.
`cascade`	A logical, default is `FALSE`. Whether to delete objects together with all the objects depending on it.

Details

When a db.data.frame object is deleted, the table/view that is associated with it is also deleted.

Value

When x is db.data.frame or table/view name, this function returns a logical value. which is TRUE if the deletion is successful.

No value is returned if x is db.Rquery

Author(s)

Author: Predictive Analytics Team at Pivotal Inc.

Maintainer: Frank McQuillan, Pivotal Inc. fmcquillan@pivotal.io

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)

delete("abalone", cid, is.temp = TRUE)

delete("abalone", cid, is.temp = FALSE)

delete("abalone", conn.id = cid)
x <- as.db.data.frame(abalone, "abalone", conn.id = cid)

lk(x, 10)

y <- as.db.data.frame(abalone, "abalone", conn.id = cid, is.temp = TRUE)

lk(y, 10)

db.existsObject("abalone", cid, is.temp = TRUE)

db.existsObject("abalone", cid, is.temp = FALSE)

delete("abalone", cid)

p <- db.objects()
p[p == "abalone"]

## Example: delete multiple tables
## all table in public schema start with "ornste"
to.delete <- db.objects("public.ornste", conn.id = cid)
for (table.name in to.delete) delete(table.name, conn.id = cid)

db.disconnect(cid, verbose = FALSE)

## End(Not run)

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