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
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
#' Database I/O generics
#'
#' @description
#' These generics are responsible for getting data into and out of the
#' database. They should be used a last resort - only use them when you can't
#' make a backend work by providing methods for DBI generics, or for dbplyr's
#' SQL generation generics. They tend to be most needed when a backend has
#' special handling of temporary tables.
#'
#' * `db_copy_to()` implements [copy_to.src_sql()] by calling
#' `db_write_table()` (which calls [DBI::dbWriteTable()]) to transfer the
#' data, then optionally adds indexes (via [sql_table_index()]) and
#' analyses (via [sql_table_analyze()]).
#'
#' * `db_compute()` implements [compute.tbl_sql()] by calling
#' [sql_query_save()] to create the table, then optionally adds indexes
#' (via [sql_table_index()]) and analyses (via [sql_table_analyze()]).
#'
#' * `db_collect()` implements [collect.tbl_sql()] using [DBI::dbSendQuery()]
#' and [DBI::dbFetch()].
#'
#' * `db_table_temporary()` is used for databases that have special naming
#' schemes for temporary tables (e.g. SQL server and SAP HANA require
#' temporary tables to start with `#`)
#'
#' @keywords internal
#' @family generic
#' @name db-io
#' @aliases NULL
NULL
#' @export
#' @rdname db-io
db_copy_to <- function(con, table, values,
overwrite = FALSE, types = NULL, temporary = TRUE,
unique_indexes = NULL, indexes = NULL,
analyze = TRUE, ...,
in_transaction = TRUE) {
UseMethod("db_copy_to")
}
#' @export
db_copy_to.DBIConnection <- function(con, table, values,
overwrite = FALSE, types = NULL, temporary = TRUE,
unique_indexes = NULL, indexes = NULL,
analyze = TRUE, ...,
in_transaction = TRUE) {
new <- db_table_temporary(con, table, temporary)
table <- new$table
temporary <- new$temporary
call <- current_env()
with_transaction(con, in_transaction, {
tryCatch(
{
table <- dplyr::db_write_table(con, table,
types = types,
values = values,
temporary = temporary,
overwrite = overwrite
)
create_indexes(con, table, unique_indexes, unique = TRUE)
create_indexes(con, table, indexes)
if (analyze) dbplyr_analyze(con, table)
},
error = function(cnd) {
cli_abort("Can't copy to table {.val {table}}", parent = cnd, call = call)
}
)
})
table
}
#' @export
#' @rdname db-io
db_compute <- function(con,
table,
sql,
temporary = TRUE,
unique_indexes = list(),
indexes = list(),
analyze = TRUE,
...) {
UseMethod("db_compute")
}
#' @export
db_compute.DBIConnection <- function(con,
table,
sql,
temporary = TRUE,
unique_indexes = list(),
indexes = list(),
analyze = TRUE,
...) {
new <- db_table_temporary(con, table, temporary)
table <- new$table
temporary <- new$temporary
table <- dbplyr_save_query(con, sql, table, temporary = temporary)
create_indexes(con, table, unique_indexes, unique = TRUE)
create_indexes(con, table, indexes)
if (analyze) dbplyr_analyze(con, table)
table
}
#' @export
#' @rdname db-io
db_collect <- function(con, sql, n = -1, warn_incomplete = TRUE, ...) {
UseMethod("db_collect")
}
#' @export
db_collect.DBIConnection <- function(con, sql, n = -1, warn_incomplete = TRUE, ...) {
res <- dbSendQuery(con, sql)
tryCatch({
out <- dbFetch(res, n = n)
if (warn_incomplete) {
res_warn_incomplete(res, "n = Inf")
}
}, finally = {
dbClearResult(res)
})
out
}
#' @export
#' @importFrom dplyr db_write_table
db_write_table.DBIConnection <- function(con,
table,
types,
values,
temporary = TRUE,
overwrite = FALSE,
...) {
tryCatch(
dbWriteTable(
con,
name = dbi_quote(table, con),
value = values,
field.types = types,
temporary = temporary,
overwrite = overwrite,
row.names = FALSE
),
error = function(cnd) {
msg <- "Can't write table {.val {table}}."
cli_abort(msg, parent = cnd)
}
)
table
}
# Utility functions ------------------------------------------------------------
dbi_quote <- function(x, con) UseMethod("dbi_quote")
dbi_quote.ident <- function(x, con) DBI::dbQuoteIdentifier(con, as.character(x))
dbi_quote.character <- function(x, con) DBI::dbQuoteString(con, x)
dbi_quote.sql <- function(x, con) DBI::SQL(as.character(x)) # nocov
create_indexes <- function(con, table, indexes = NULL, unique = FALSE, ...) {
if (is.null(indexes)) {
return()
}
indexes <- as.list(indexes)
for (index in indexes) {
dbplyr_create_index(con, table, index, unique = unique, ...)
}
}
# Don't use `tryCatch()` because it messes with the callstack
with_transaction <- function(con, in_transaction, code) {
if (in_transaction) {
dbBegin(con)
on.exit(dbRollback(con))
}
code
if (in_transaction) {
on.exit()
dbCommit(con)
}
}
#' @export
#' @rdname db-io
db_table_temporary <- function(con, table, temporary) {
UseMethod("db_table_temporary")
}
#' @export
db_table_temporary.DBIConnection <- function(con, table, temporary) {
list(
table = table,
temporary = temporary
)
}
|
