1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
NULL
# Coercion rules ---------------------------------------------------------------
coerce <- function(sqlvar, from, to) {
list(from = from, to = to)
}
sqlDate <- function() {
coerce(
function(x) as.integer(x),
function(x) {
stopifnot(is.integer(x))
structure(x, class = "Date")
}
)
}
sqlDateTime <- function() {
coerce(
function(x) as.numeric(x),
function(x) {
stopifnot(is.numeric(x))
structure(x, class = c("POSIXct", "POSIXt"), tzone = "UTC")
}
)
}
sqlSerialize <- function() {
coerce(
function(x) {
lapply(x, serialize, connection = NULL)
},
function(x) {
lapply(x, unserialize)
}
)
}
sqlBoolean <- function() {
coerce(
function(x) as.integer(x),
function(x) as.logical(x)
)
}
sqlFactor <- function(levels) {
coerce(
function(x) as.integer(x),
function(x) factor(x, levels = levels)
)
}
|
