func-methods: Mathematical functions that take 'db.obj' objects as the...

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

Mathematical functions that take db.obj objects as the argument

Description

Functions that apply onto db.obj objects

Usage

## S4 method for signature 'db.obj'
exp(x)
## S4 method for signature 'db.obj'
abs(x)
## S4 method for signature 'db.obj'
log(x, ...)
## S4 method for signature 'db.obj'
log10(x)
## S4 method for signature 'db.obj'
sign(x)
## S4 method for signature 'db.obj'
sqrt(x)
## S4 method for signature 'db.obj'
factorial(x)
## S4 method for signature 'db.obj'
sin(x)
## S4 method for signature 'db.obj'
cos(x)
## S4 method for signature 'db.obj'
tan(x)
## S4 method for signature 'db.obj'
asin(x)
## S4 method for signature 'db.obj'
acos(x)
## S4 method for signature 'db.obj'
atan(x)
## S4 method for signature 'db.obj,db.obj'
atan2(y, x)
## S4 method for signature 'db.obj,numeric'
atan2(y, x)
## S4 method for signature 'numeric,db.obj'
atan2(y, x)

Arguments

x,y	db.obj object. The function applies to each column of the db.obj object. If a column is an array, then the function applies onto each element of the array. If the data type of the column makes no sense to be used in the function, then a null value is returned.
...	Extra parameters. Not implemented.

Value

db.Rquery object, which contains the SQL query that computes the operations.

Note

A meaningful expression is generated only when the .col.data_type is "numeric", otherwise a "NULL" value is generated.

Author(s)

Author: Predictive Analytics Team at Pivotal Inc.

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

See Also

db.Rquery contains a SQL query that does the operations.

Examples

## Not run: 
## get the help for a method
## help("+,db.obj,db.obj-method")


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

## create a table from the example data.frame "abalone"
delete("abalone", conn.id = cid)
x <- as.db.data.frame(abalone, "abalone", conn.id = cid)

x$rings <- exp(x$rings) # change the values

x$area <- log((x$length + 1) * (x$height + 1)) # add a new column

lk(x$area, 10) # view the actual values computed in database

db.disconnect(cid, verbose = FALSE)

## End(Not run)

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