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
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
| #lang racket/base
;; Copyright (c) 2018 Joel Dueck.
;;
;; Licensed under the Apache License, Version 2.0 (the "License");
;; you may not use this file except in compliance with the License.
;; A copy of the License is included with this source code, in the
;; file "LICENSE.txt".
;; You may also obtain a copy of the License at
;;
;; http://www.apache.org/licenses/LICENSE-2.0
;;
;; Unless required by applicable law or agreed to in writing, software
;; distributed under the License is distributed on an "AS IS" BASIS,
;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;; See the License for the specific language governing permissions and
;; limitations under the License.
;;
;; Author contact information:
;; joel@jdueck.net
;; https://joeldueck.com
;; -------------------------------------------------------------------------
;; Provides a very light set of utility functions for a SQLite database.
;; These functions are completely agnostic as to the database schema.
;; These functions are NOT SAFE for use with data provided by untrusted users!
(require db/sqlite3
db/base
racket/list
racket/match
racket/function
racket/contract
sugar/coerce)
(module+ test
(require rackunit))
(provide (all-from-out db/base db/sqlite3))
(provide sqltools:dbc
sqltools:log-queries?)
(provide
(contract-out
;; Utility functions
[log-query (string? . -> . void?)]
[vector->hash (vector? (listof symbolish?) . -> . hash?)]
[backtick (stringish? . -> . string?)]
[list->sql-fields ((listof stringish?) . -> . string?)]
[list->sql-values ((listof stringish?) . -> . string?)]
[list->sql-parameters ((listof any/c) . -> . string?)]
[bool->int (any/c . -> . exact-integer?)]
[int->bool (exact-integer? . -> . boolean?)]
;; Simple SQL makers
[make-table-schema ((string? (listof stringish?))
(#:primary-key-cols (listof stringish?))
. ->* . string?)]
[make-insert/replace-query (stringish? (listof stringish?) . -> . string?)]
[make-insert-rows-query (stringish? (listof stringish?) (listof (listof stringish?)) . -> . string?)]
[make-select-query (stringish? (listof stringish?) #:where stringish? . -> . string?)]
;; Database operations
[init-db! ((pathish?) () #:rest (listof string?) . ->* . void?)]
[query! ((string?) () #:rest (listof any/c) . ->* . void?)]
[select-rows! (case->
(stringish? (listof stringish?) any/c . -> . (or/c empty? hash?))
(string? (listof stringish?) . -> . (or/c empty? hash?)))]))
;; ~~~ Private use ~~~
(define uninitialized-connection "No DB connection!")
(define (weave xs ys)
(for/fold [(woven null)
#:result (reverse woven)]
([x (in-list xs)]
[y (in-list ys)])
(cons y (cons x woven))))
(define (sql-val v)
(cond [(string? v) (string-append "\"" v "\"")]
[else (format "~a" v)]))
;; ~~~ Provided parameters ~~~
(define sqltools:dbc (make-parameter uninitialized-connection))
(define sqltools:log-queries? (make-parameter #f))
;; ~~~ Provided utility functions ~~~
(define (backtick str) (format "`~a`" str))
(define (list->sql-fields fields) (apply string-append (add-between (map backtick fields) ", ")))
(define (list->sql-values vals)
(string-append "(" (apply string-append (add-between (map sql-val vals) ", ")) ")"))
(define (list->sql-parameters fields)
(apply string-append (add-between (map (λ(x) (format "?~a" (add1 x))) (range (length fields))) ", ")))
;; For storing/reading boolean values (SQLite uses integers)
(define (bool->int b?)
(cond [b? 1] [else 0]))
(define (int->bool i)
(not (= i 0)))
;; TESTING: utility functions…
(module+ test
(check-equal? (backtick "field") "`field`")
(check-equal? (list->sql-fields '("f1" "f2" "f3")) "`f1`, `f2`, `f3`")
(check-equal? (list->sql-fields '(f1 f2 f3)) "`f1`, `f2`, `f3`") ; Can use symbols too
(check-equal? (list->sql-parameters '("name" "rank" "serial")) "?1, ?2, ?3")
(check-equal? (list->sql-parameters '(name rank serial)) "?1, ?2, ?3")
(check-equal? (list->sql-values '(100 "hello" 3)) "(100, \"hello\", 3)")
(check-equal? (weave '(x y z) '(1 2 3)) '(x 1 y 2 z 3))
(check-equal? (bool->int #f) 0)
(check-equal? (bool->int #t) 1)
(check-equal? (bool->int "xblargh") 1)
(check-equal? (int->bool 0) #f)
(check-equal? (int->bool 1) #t)
(check-equal? (int->bool -1) #t)
(check-equal? (int->bool 37) #t)
(check-exn exn:fail? (lambda () (int->bool "x"))))
;; ~~~ Public functions ~~~
;; Prints to stdout if logging is on
(define (log-query q) (unless (not (sqltools:log-queries?)) (println q)))
;; Using a list of field names, convert a vector into a hash that uses the
;; field names (in symbol form) for keys.
;; Racket’s db functions all return vectors; hashes are much easier to use.
;; If fields and v are not equal in length, the unpairable elements are omitted
;; from the hash!
(define (vector->hash v fields)
(cond [(zero? (vector-length v)) null]
[else (let ([keys (map ->symbol fields)]
[vals (vector->list v)])
(apply hash (weave keys vals)))]))
;; TESTING: vector->hash...
(module+ test
(let ([test-row '#("Joe" "PFC" 123)]
[test-cols-SYMBOL '(name rank serial)]
[test-cols-STRING '("name" "rank" "serial")]
[desired-result '#hash((serial . 123) (rank . "PFC") (name . "Joe"))])
(check-equal? (vector->hash test-row test-cols-SYMBOL) desired-result)
(check-equal? (vector->hash test-row test-cols-STRING) desired-result))
;; Behavior when v and fields are unequal in length:
(check-equal? (vector->hash '#("foo" "bar") '(a b c))
'#hash((a . "foo") (b . "bar")))
(check-equal? (vector->hash '#("foo" "bar" "baz") '(a b))
'#hash((a . "foo") (b . "bar"))))
;; Create a simple table schema from a list of fields, optionally specifying
;; primary key
(define (make-table-schema tablename fields #:primary-key-cols [primary-cols '()])
(define primary-key
(format "PRIMARY KEY (~a)"
(list->sql-fields (if (empty? primary-cols) (list (first fields)) primary-cols))))
(format "CREATE TABLE IF NOT EXISTS `~a` (~a, ~a);"
tablename
(list->sql-fields fields)
primary-key))
;; Create a query that inserts a row if it doesn’t exist (based on the first
;; column only), or updates it if it does. The returned query is parameterized,
;; and must be used with a list of values equal in length to the number of
;; fields given.
(define (make-insert/replace-query tablename fields)
(format "INSERT OR REPLACE INTO `~a` (`rowid`, ~a) VALUES ((SELECT `rowid` FROM `~a` WHERE `~a`= ?1), ~a)"
tablename
(list->sql-fields fields)
tablename
(first fields)
(list->sql-parameters fields)))
;; Create a query that inserts multiple rows.
(define (make-insert-rows-query tablename fields rows)
(define row-values
(apply string-append (add-between (map list->sql-values rows) ", ")))
(format "INSERT INTO `~a` (~a) VALUES ~a;" tablename (list->sql-fields fields) row-values))
;; Simple row selection
(define (make-select-query table fields #:where where-clause)
(format "SELECT ~a FROM `~a` WHERE ~a"
(list->sql-fields fields)
table
where-clause))
;; TESTING: SQL query makers...
(module+ test
(check-equal? (make-table-schema 'posts '(title date))
"CREATE TABLE IF NOT EXISTS `posts` (`title`, `date`, PRIMARY KEY (`title`));")
(check-equal? (make-table-schema "posts" '("title" "date"))
"CREATE TABLE IF NOT EXISTS `posts` (`title`, `date`, PRIMARY KEY (`title`));")
(check-equal? (make-table-schema 'posts '(title date) #:primary-key-cols '(author date))
"CREATE TABLE IF NOT EXISTS `posts` (`title`, `date`, PRIMARY KEY (`author`, `date`));")
(check-equal? (make-insert/replace-query 'posts '(author title))
(string-append "INSERT OR REPLACE INTO `posts` (`rowid`, `author`, `title`) "
"VALUES ((SELECT `rowid` FROM `posts` WHERE `author`= ?1), ?1, ?2)"))
(check-equal? (make-insert-rows-query 'series '(id name num) '((1 "Journal" 11) (2 "Ideas" 4)))
(string-append "INSERT INTO `series` (`id`, `name`, `num`) "
"VALUES (1, \"Journal\", 11), (2, \"Ideas\", 4);"))
(check-equal? (make-select-query 'posts '(author title) #:where 1)
"SELECT `author`, `title` FROM `posts` WHERE 1"))
(define (good-connection?)
(and (connection? (sqltools:dbc)) (connected? (sqltools:dbc))))
;; Initialize the database connection, creating the database if it does not yet exist
;; and running any provided queries (e.g., "CREATE TABLE IF NOT EXISTS...")
(define (init-db! filename . qs)
(cond [(good-connection?) (disconnect (sqltools:dbc))])
(sqltools:dbc (sqlite3-connect #:database filename #:mode 'create))
(unless (empty? qs)
(for ([q (in-list qs)])
(query! q))))
;; Run a query with logging (if enabled) and return the result
(define (query! q . parameters)
(unless (good-connection?) (error "(query!) DB not connected"))
(log-query q)
(cond [(empty? parameters) (query-exec (sqltools:dbc) q)]
[else (apply query-exec (sqltools:dbc) q parameters)]))
;; Run a SELECT query, return a hash with field names as keys
(define select-rows!
(case-lambda
;; Use arbitrary query
[(query fieldnames)
(unless (good-connection?) (error "(select-rows!) DB not connected"))
(log-query query)
(define result (query-rows (sqltools:dbc) query))
(map (curryr vector->hash fieldnames) result)]
;; Use a simple SELECT FROM WHERE template
[(table fields where-clause)
(unless (good-connection?) (error "(select-rows!) DB not connected"))
(define query (make-select-query table fields #:where where-clause))
(log-query query)
(define result (query-rows (sqltools:dbc) query))
(map (curryr vector->hash fields) result)]))
;; TESTING: database connection state and queries
(module+ test
(define TESTDB "SQLITE-TOOLS-TEST.sqlite")
;; Check that things start out uninitialized and that queries don’t work
(check-equal? (sqltools:dbc) uninitialized-connection)
(check-false (file-exists? TESTDB))
(check-exn exn:fail? (lambda () (query! "SELECT 1")))
(check-exn exn:fail? (lambda () (select-rows! 'posts '(title) 1)))
;; Initialize db connection, create file with no schema
(test-begin
(check-equal? (init-db! TESTDB) (void))
(check-true (file-exists? TESTDB))
(delete-file TESTDB))
;; Initialize new db/connection, create file with schema, check that
;; simple queries return expected results
(test-begin
(check-equal? (init-db! TESTDB (make-table-schema 'posts '(title date))) (void))
(check-true (file-exists? TESTDB))
(check-equal? (select-rows! (make-select-query 'posts '(title date) #:where 1) '(title date)) null)
(check-equal? (query! (make-insert/replace-query 'posts '(title date)) "Hello" "2018-08-10") (void))
(check-equal? (select-rows! 'posts '(title date) "`date`='2018-08-10'")
'(#hash((title . "Hello") (date . "2018-08-10")))))
;; Clean up
(disconnect (sqltools:dbc))
(sqltools:dbc uninitialized-connection)
(delete-file TESTDB))
|
