PivotalR (version 0.1.18.5)

subset-methods: 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 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.

See Also

[-methods Operator to extract elements

Examples

# NOT RUN {
<!-- %% @test .port Database port number -->
<!-- %% @test .dbname Database name -->
## 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)
# }