db: split off db/util/datetime module

collects/db/TODO

@@ -1,3 +1,4 @@
+internal docs
 ----
 
 Testing

collects/db/private/generic/main.rkt

@@ -1,14 +1,68 @@
 #lang racket/base
-(require "interfaces.rkt"
+(require racket/contract
+         "interfaces.rkt"
          "sql-data.rkt"
          "functions.rkt")
 (provide (struct-out simple-result)
          (struct-out rows-result)
          statement-binding?
-         (except-out (all-from-out "sql-data.rkt")
-                     make-sql-bits/bytes
-                     sql-bits-bv
-                     align-sql-bits
-                     int8? int16? int24? int32? int64?
-                     uint8?)
          (all-from-out "functions.rkt"))
+
+(provide sql-null
+         sql-null?
+         sql-null->false
+         false->sql-null)
+
+(provide/contract
+ [struct sql-date ([year exact-integer?]
+                   [month (integer-in 0 12)]
+                   [day (integer-in 0 31)])]
+ [struct sql-time ([hour (integer-in 0 23)]
+                   [minute (integer-in 0 59)]
+                   [second (integer-in 0 61)] ;; leap seconds
+                   [nanosecond (integer-in 0 (sub1 #e1e9))]
+                   [tz (or/c #f exact-integer?)])]
+ [struct sql-timestamp ([year exact-integer?]
+                        [month (integer-in 0 12)]
+                        [day (integer-in 0 31)]
+                        [hour (integer-in 0 23)]
+                        [minute (integer-in 0 59)]
+                        [second (integer-in 0 61)]
+                        [nanosecond (integer-in 0 (sub1 #e1e9))]
+                        [tz (or/c #f exact-integer?)])]
+ [struct sql-interval ([years exact-integer?]
+                       [months exact-integer?]
+                       [days exact-integer?]
+                       [hours exact-integer?]
+                       [minutes exact-integer?]
+                       [seconds exact-integer?]
+                       [nanoseconds exact-integer?])]
+
+ [sql-day-time-interval?
+  (-> any/c boolean?)]
+ [sql-year-month-interval?
+  (-> any/c boolean?)]
+ [sql-interval->sql-time
+  (->* (sql-interval?) (any/c)
+       any)]
+ [sql-time->sql-interval
+  (-> sql-time? sql-day-time-interval?)]
+
+ [make-sql-bits
+  (-> exact-nonnegative-integer? sql-bits?)]
+ [sql-bits?
+  (-> any/c boolean?)]
+ [sql-bits-length
+  (-> sql-bits? exact-nonnegative-integer?)]
+ [sql-bits-ref
+  (-> sql-bits? exact-nonnegative-integer? boolean?)]
+ [sql-bits-set!
+  (-> sql-bits? exact-nonnegative-integer? boolean? void?)]
+ [sql-bits->list
+  (-> sql-bits? (listof boolean?))]
+ [list->sql-bits
+  (-> (listof boolean?) sql-bits?)]
+ [sql-bits->string
+  (-> sql-bits? string?)]
+ [string->sql-bits
+  (-> string? sql-bits?)])

collects/db/private/generic/sql-convert.rkt

@@ -1,28 +1,10 @@
 #lang racket/base
-(require racket/match
+(require "sql-data.rkt")
-         (prefix-in srfi: srfi/19)
-         "sql-data.rkt")
 
-#|
+;; ========================================
-parse-<type> : string -> racket-datum
 
-Takes the textual wire representation of <type> as a string, and
+(provide parse-decimal          ;; used by pg, mysql
-produces the corresponding racket datum.
+         parse-exact-fraction)  ;; used by pg
-
-No conversion may be passed sql-null.
-|#
-
-(provide parse-char1
-         parse-decimal
-         parse-date
-         parse-time
-         parse-time-tz
-         parse-timestamp
-         parse-timestamp-tz
-         parse-interval)
-
-(define (parse-char1 s)
-  (string-ref s 0))
 
 (define (parse-decimal s)
   (cond [(equal? s "NaN") +nan.0]
@@ -34,102 +16,19 @@ No conversion may be passed sql-null.
          => (lambda (m)
               (+ (string->number (cadr m))
                  (parse-exact-fraction (caddr m))))]
-        [else (parse-error "numeric" s)]))
+        [else
+         (error 'parse-decimal "internal error: cannot parse ~s as decimal" s)]))
 
 (define (parse-exact-fraction s)
   ;; eg: (parse-exact-fraction "12") = 12/100
   (/ (string->number s)
      (expt 10 (string-length s))))
 
-(define (parse-date d)
-  (srfi-date->sql-date
-   (srfi:string->date d "~Y-~m-~d")))
-
-(define time/ns-rx #rx"^[0-9]*:[0-9]*:[0-9]*\\.([0-9]*)")
-(define timestamp/ns-rx #rx"^.* [0-9]*:[0-9]*:[0-9]*\\.([0-9]*)")
-
-(define (ns-of t rx)
-  (let ([m (regexp-match rx t)])
-    (if m
-        (* #e1e9 (parse-exact-fraction (cadr m)))
-        0)))
-
-(define (parse-time t)
-  (srfi-date->sql-time
-   (srfi:string->date t "~k:~M:~S")
-   (ns-of t time/ns-rx)))
-
-(define (parse-time-tz t)
-  (srfi-date->sql-time-tz
-   (srfi:string->date t "~k:~M:~S~z")
-   (ns-of t time/ns-rx)))
-
-(define (parse-timestamp t)
-  (srfi-date->sql-timestamp
-   (srfi:string->date t "~Y-~m-~d ~k:~M:~S")
-   (ns-of t timestamp/ns-rx)))
-
-(define (parse-timestamp-tz t)
-  (srfi-date->sql-timestamp-tz
-   (srfi:string->date t "~Y-~m-~d ~k:~M:~S~z")
-   (ns-of t timestamp/ns-rx)))
-
-(define interval-rx
-  (regexp
-   (string-append "^"
-                  "(?:(-?[0-9]*) years? *)?"
-                  "(?:(-?[0-9]*) mons? *)?"
-                  "(?:(-?[0-9]*) days? *)?"
-                  "(?:(-?)([0-9]*):([0-9]*):([0-9]*)(?:\\.([0-9]*))?)?"
-                  "$")))
-
-(define (parse-interval s)
-  (define (to-num m)
-    (if m (string->number m) 0))
-  (define match-result (regexp-match interval-rx s))
-  (match match-result
-    [(list _whole years months days tsign hours mins secs fsec)
-     (let* ([years (to-num years)]
-            [months (to-num months)]
-            [days (to-num days)]
-            [sg (if (equal? tsign "-") - +)]
-            [hours (sg (to-num hours))]
-            [mins (sg (to-num mins))]
-            [secs (sg (to-num secs))]
-            [nsecs (if fsec
-                       (let ([flen (string-length fsec)])
-                         (* (string->number (substring fsec 0 (min flen 9)))
-                            (expt 10 (- 9 (min flen 9)))))
-                       0)])
-       (sql-interval years months days hours mins secs nsecs))]))
-
-
-;; ----------------------------------------
-
-;; parse-error : string string -> (raises error)
-(define (parse-error type rep)
-  (error 'query* "internal error: cannot parse as SQL type ~s: ~e"
-         type rep))
-
 ;; ========================================
 
-#|
+(provide marshal-decimal        ;; pg, odbc (?!)
-marshal-<type> : fsym index datum -> string
+         exact->decimal-string  ;; tests (?)
-
+         exact->scaled-integer) ;; odbc
-Takes a racket datum and converts it into <type>'s text wire format.
-No conversion may be passed sql-null.
-|#
-
-(provide marshal-decimal
-         marshal-date
-         marshal-time
-         marshal-time-tz
-         marshal-timestamp
-         marshal-timestamp-tz
-         marshal-interval
-
-         exact->decimal-string
-         exact->scaled-integer)
 
 (define (marshal-decimal f i n)
   (cond [(not (real? n))
@@ -193,49 +92,9 @@ No conversion may be passed sql-null.
         (values n 0)))
   (loop n factor))
 
-(define (marshal-date f i d)
+;; ========================================
-  (unless (sql-date? d)
-    (marshal-error f i "date" d))
-  (srfi:date->string (sql-datetime->srfi-date d) "~Y-~m-~d"))
 
-(define (marshal-time f i t)
+(provide marshal-error)
-  (unless (sql-time? t)
-    (marshal-error f i "time" t))
-  (srfi:date->string (sql-datetime->srfi-date t) "~k:~M:~S.~N"))
-
-(define (marshal-time-tz f i t)
-  (unless (sql-time? t)
-    (marshal-error f i "time" t))
-  (srfi:date->string (sql-datetime->srfi-date t) "~k:~M:~S.~N~z"))
-
-(define (marshal-timestamp f i t)
-  (unless (sql-timestamp? t)
-    (marshal-error f i "timestamp" t))
-  (srfi:date->string (sql-datetime->srfi-date t) "~Y-~m-~d ~k:~M:~S.~N"))
-
-(define (marshal-timestamp-tz f i t)
-  (unless (sql-timestamp? t)
-    (marshal-error f i "timestamp" t))
-  (srfi:date->string (sql-datetime->srfi-date t) "~Y-~m-~d ~k:~M:~S.~N~z"))
-
-(define (marshal-interval f i t)
-  (define (tag num unit)
-    (if (zero? num) "" (format "~a ~a " num unit)))
-  (match t
-    [(sql-interval years months days hours minutes seconds nanoseconds)
-     ;; Note: we take advantage of PostgreSQL's liberal interval parser
-     ;; and we acknowledge its micro-second precision.
-     (string-append (tag years "years")
-                    (tag months "months")
-                    (tag days "days")
-                    (tag hours "hours")
-                    (tag minutes "minutes")
-                    (tag seconds "seconds")
-                    (tag (quotient nanoseconds 1000) "microseconds"))]
-    [else
-     (marshal-error f i "interval" t)]))
-
-;; ----------------------------------------
 
 ;; marshal-error : string datum -> (raises error)
 (define (marshal-error f i type datum)

collects/db/private/generic/sql-data.rkt

@@ -1,11 +1,13 @@
 #lang racket/base
-(require racket/contract
+(provide (all-defined-out))
-         racket/match
-         (prefix-in srfi: srfi/19))
 
 ;; SQL Data
 ;; Datatypes for things that have no appropriate corresponding Scheme datatype
 
+;; ----------------------------------------
+
+;; NULL
+
 (define sql-null
   (let ()
     (define-struct sql-null ())
@@ -24,10 +26,11 @@
       sql-null
       x))
 
-;; ----
+;; ----------------------------------------
+
+;; Dates and times
 
 #|
-
 ** problems with Racket date:
 
  - fields in wrong order
@@ -39,7 +42,6 @@
 
  - fields in wrong order
  - timezone offset too limited
-
 |#
 
 (define-struct sql-date (year month day) #:transparent)
@@ -74,55 +76,6 @@
 
 ;; ----
 
-(define (sql-datetime->srfi-date datetime)
-  (match datetime
-    [(struct sql-date (year month day))
-     (srfi:make-date 0 0 0 0 day month year 0)]
-    [(struct sql-time (hour minute second nanosecond tz))
-     (srfi:make-date nanosecond second minute hour 0 0 0 (or tz 0))]
-    [(struct sql-timestamp (year month day hour minute second nanosecond tz))
-     (srfi:make-date nanosecond second minute hour day month year (or tz 0))]
-    [else
-     (raise-type-error 'sql-datetime->srfi-date
-                       "sql-date, sql-time, or sql-timestamp"
-                       datetime)]))
-
-(define (srfi-date->sql-date date)
-  (make-sql-date (srfi:date-year date)
-                 (srfi:date-month date)
-                 (srfi:date-day date)))
-
-(define (srfi-date->sql-time* date tz? ns)
-  (make-sql-time (srfi:date-hour date)
-                 (srfi:date-minute date)
-                 (srfi:date-second date)
-                 (or ns (srfi:date-nanosecond date))
-                 (and tz? (srfi:date-zone-offset date))))
-
-(define (srfi-date->sql-time date [ns #f])
-  (srfi-date->sql-time* date #f ns))
-
-(define (srfi-date->sql-time-tz date [ns #f])
-  (srfi-date->sql-time* date #t ns))
-
-(define (srfi-date->sql-timestamp* date tz? ns)
-  (make-sql-timestamp (srfi:date-year date)
-                      (srfi:date-month date)
-                      (srfi:date-day date)
-                      (srfi:date-hour date)
-                      (srfi:date-minute date)
-                      (srfi:date-second date)
-                      (or ns (srfi:date-nanosecond date))
-                      (and tz? (srfi:date-zone-offset date))))
-
-(define (srfi-date->sql-timestamp date [ns #f])
-  (srfi-date->sql-timestamp* date #f ns))
-
-(define (srfi-date->sql-timestamp-tz date [ns #f])
-  (srfi-date->sql-timestamp* date #t ns))
-
-;; ----
-
 (define (sql-day-time-interval? x)
   (and (sql-interval? x)
        (zero? (sql-interval-years x))
@@ -136,17 +89,6 @@
        (zero? (sql-interval-seconds x))
        (zero? (sql-interval-nanoseconds x))))
 
-(define (sql-day-time-interval->seconds x)
-  (+ (* (sql-interval-hours x) 60 60)
-     (* (sql-interval-minutes x) 60)
-     (sql-interval-seconds x)
-     (/ (sql-interval-nanoseconds x) #i1e9)))
-
-(define (same-signs? w x y z)
-  (define some-pos? (or (positive? w) (positive? x) (positive? y) (positive? z)))
-  (define some-neg? (or (negative? w) (negative? x) (negative? y) (negative? z)))
-  (not (and some-pos? some-neg?)))
-
 (define no-arg (gensym))
 
 (define (sql-interval->sql-time x [default no-arg])
@@ -176,70 +118,9 @@
                 (sql-time-second x)
                 (sql-time-nanosecond x)))
 
-;; ----
+;; ----------------------------------------
 
-;; Note: MySQL allows 0 month, 0 day, etc.
+;; Bits
-
-(provide sql-null
-         sql-null?
-         sql-null->false
-         false->sql-null)
-(provide/contract
- [struct sql-date ([year exact-integer?]
-                   [month (integer-in 0 12)]
-                   [day (integer-in 0 31)])]
- [struct sql-time ([hour (integer-in 0 23)]
-                   [minute (integer-in 0 59)]
-                   [second (integer-in 0 61)] ;; leap seconds
-                   [nanosecond (integer-in 0 (sub1 #e1e9))]
-                   [tz (or/c #f exact-integer?)])]
- [struct sql-timestamp ([year exact-integer?]
-                        [month (integer-in 0 12)]
-                        [day (integer-in 0 31)]
-                        [hour (integer-in 0 23)]
-                        [minute (integer-in 0 59)]
-                        [second (integer-in 0 61)]
-                        [nanosecond (integer-in 0 (sub1 #e1e9))]
-                        [tz (or/c #f exact-integer?)])]
- [struct sql-interval ([years exact-integer?]
-                       [months exact-integer?]
-                       [days exact-integer?]
-                       [hours exact-integer?]
-                       [minutes exact-integer?]
-                       [seconds exact-integer?]
-                       [nanoseconds exact-integer?])]
-
- [sql-datetime->srfi-date
-  (-> (or/c sql-date? sql-time? sql-timestamp?)
-      srfi:date?)]
- [srfi-date->sql-date
-  (-> srfi:date? sql-date?)]
- [srfi-date->sql-time
-  (->* (srfi:date?) ((or/c exact-nonnegative-integer? #f))
-       sql-time?)]
- [srfi-date->sql-time-tz
-  (->* (srfi:date?) ((or/c exact-nonnegative-integer? #f))
-       sql-time?)]
- [srfi-date->sql-timestamp
-  (->* (srfi:date?) ((or/c exact-nonnegative-integer? #f))
-       sql-timestamp?)]
- [srfi-date->sql-timestamp-tz
-  (->* (srfi:date?) ((or/c exact-nonnegative-integer? #f))
-       sql-timestamp?)]
-
- [sql-day-time-interval?
-  (-> any/c boolean?)]
- [sql-year-month-interval?
-  (-> any/c boolean?)]
- [sql-day-time-interval->seconds
-  (-> sql-day-time-interval? rational?)]
- [sql-interval->sql-time
-  (->* (sql-interval?) (any/c)
-       any)]
- [sql-time->sql-interval
-  (-> sql-time? sql-day-time-interval?)])
-
-;; ----
 
 #|
 A sql-bits is (sql-bits len bv offset)
@@ -344,30 +225,6 @@ byte. (Because that's PostgreSQL's binary format.) For example:
       (bv-set! bv* (+ i offset*) (bv-ref bv0 (+ offset0 i))))
     (sql-bits len bv* offset*)))
 
-(provide make-sql-bits/bytes
-         sql-bits-bv
-         align-sql-bits)
-
-(provide/contract
- [make-sql-bits
-  (-> exact-nonnegative-integer? sql-bits?)]
- [sql-bits?
-  (-> any/c boolean?)]
- [sql-bits-length
-  (-> sql-bits? exact-nonnegative-integer?)]
- [sql-bits-ref
-  (-> sql-bits? exact-nonnegative-integer? boolean?)]
- [sql-bits-set!
-  (-> sql-bits? exact-nonnegative-integer? boolean? void?)]
- [sql-bits->list
-  (-> sql-bits? (listof boolean?))]
- [list->sql-bits
-  (-> (listof boolean?) sql-bits?)]
- [sql-bits->string
-  (-> sql-bits? string?)]
- [string->sql-bits
-  (-> string? sql-bits?)])
-
 ;; ----------------------------------------
 
 ;; Predicates

collects/db/private/postgresql/dbsystem.rkt

@@ -1,9 +1,12 @@
 #lang racket/base
 (require racket/class
          racket/list
+         racket/match
+         (prefix-in srfi: srfi/19)
          "../generic/interfaces.rkt"
          "../generic/sql-data.rkt"
          "../generic/sql-convert.rkt"
+         "../../util/datetime.rkt"
          "../../util/geometry.rkt"
          "../../util/postgresql.rkt"
          (only-in "message.rkt" field-dvec->typeid))
@@ -130,6 +133,114 @@ record = cols:int4 (typeoid:int4 len/-1:int4 data:byte^len)^cols
 
 |#
 
+;; Text readers
+
+(define (parse-date d)
+  (srfi-date->sql-date
+   (srfi:string->date d "~Y-~m-~d")))
+
+(define time/ns-rx #rx"^[0-9]*:[0-9]*:[0-9]*\\.([0-9]*)")
+(define timestamp/ns-rx #rx"^.* [0-9]*:[0-9]*:[0-9]*\\.([0-9]*)")
+
+(define (ns-of t rx)
+  (let ([m (regexp-match rx t)])
+    (if m
+        (* #e1e9 (parse-exact-fraction (cadr m)))
+        0)))
+
+(define (parse-time t)
+  (srfi-date->sql-time
+   (srfi:string->date t "~k:~M:~S")
+   (ns-of t time/ns-rx)))
+
+(define (parse-time-tz t)
+  (srfi-date->sql-time-tz
+   (srfi:string->date t "~k:~M:~S~z")
+   (ns-of t time/ns-rx)))
+
+(define (parse-timestamp t)
+  (srfi-date->sql-timestamp
+   (srfi:string->date t "~Y-~m-~d ~k:~M:~S")
+   (ns-of t timestamp/ns-rx)))
+
+(define (parse-timestamp-tz t)
+  (srfi-date->sql-timestamp-tz
+   (srfi:string->date t "~Y-~m-~d ~k:~M:~S~z")
+   (ns-of t timestamp/ns-rx)))
+
+(define interval-rx
+  (regexp
+   (string-append "^"
+                  "(?:(-?[0-9]*) years? *)?"
+                  "(?:(-?[0-9]*) mons? *)?"
+                  "(?:(-?[0-9]*) days? *)?"
+                  "(?:(-?)([0-9]*):([0-9]*):([0-9]*)(?:\\.([0-9]*))?)?"
+                  "$")))
+
+(define (parse-interval s)
+  (define (to-num m)
+    (if m (string->number m) 0))
+  (define match-result (regexp-match interval-rx s))
+  (match match-result
+    [(list _whole years months days tsign hours mins secs fsec)
+     (let* ([years (to-num years)]
+            [months (to-num months)]
+            [days (to-num days)]
+            [sg (if (equal? tsign "-") - +)]
+            [hours (sg (to-num hours))]
+            [mins (sg (to-num mins))]
+            [secs (sg (to-num secs))]
+            [nsecs (if fsec
+                       (let ([flen (string-length fsec)])
+                         (* (string->number (substring fsec 0 (min flen 9)))
+                            (expt 10 (- 9 (min flen 9)))))
+                       0)])
+       (sql-interval years months days hours mins secs nsecs))]))
+
+;; Text writers
+
+(define (marshal-date f i d)
+  (unless (sql-date? d)
+    (marshal-error f i "date" d))
+  (srfi:date->string (sql-datetime->srfi-date d) "~Y-~m-~d"))
+
+(define (marshal-time f i t)
+  (unless (sql-time? t)
+    (marshal-error f i "time" t))
+  (srfi:date->string (sql-datetime->srfi-date t) "~k:~M:~S.~N"))
+
+(define (marshal-time-tz f i t)
+  (unless (sql-time? t)
+    (marshal-error f i "time" t))
+  (srfi:date->string (sql-datetime->srfi-date t) "~k:~M:~S.~N~z"))
+
+(define (marshal-timestamp f i t)
+  (unless (sql-timestamp? t)
+    (marshal-error f i "timestamp" t))
+  (srfi:date->string (sql-datetime->srfi-date t) "~Y-~m-~d ~k:~M:~S.~N"))
+
+(define (marshal-timestamp-tz f i t)
+  (unless (sql-timestamp? t)
+    (marshal-error f i "timestamp" t))
+  (srfi:date->string (sql-datetime->srfi-date t) "~Y-~m-~d ~k:~M:~S.~N~z"))
+
+(define (marshal-interval f i t)
+  (define (tag num unit)
+    (if (zero? num) "" (format "~a ~a " num unit)))
+  (match t
+    [(sql-interval years months days hours minutes seconds nanoseconds)
+     ;; Note: we take advantage of PostgreSQL's liberal interval parser
+     ;; and we acknowledge its micro-second precision.
+     (string-append (tag years "years")
+                    (tag months "months")
+                    (tag days "days")
+                    (tag hours "hours")
+                    (tag minutes "minutes")
+                    (tag seconds "seconds")
+                    (tag (quotient nanoseconds 1000) "microseconds"))]
+    [else
+     (marshal-error f i "interval" t)]))
+
 ;; Binary readers
 
 (define (recv-bits x)
@@ -227,8 +338,7 @@ record = cols:int4 (typeoid:int4 len/-1:int4 data:byte^len)^cols
            +nan.0])))
 |#
 
-(define-values (c-parse-char1
+(define-values (c-parse-date
-                c-parse-date
                 c-parse-time
                 c-parse-time-tz
                 c-parse-timestamp
@@ -236,8 +346,7 @@ record = cols:int4 (typeoid:int4 len/-1:int4 data:byte^len)^cols
                 c-parse-interval
                 c-parse-decimal)
   (let ([c (lambda (f) (lambda (x) (f (bytes->string/utf-8 x))))])
-    (values (c parse-char1)
+    (values (c parse-date)
-            (c parse-date)
             (c parse-time)
             (c parse-time-tz)
             (c parse-timestamp)

collects/db/scribblings/config.rkt

@@ -14,7 +14,8 @@
 (void
  (interaction-eval #:eval the-eval
                    (require racket/class
-                            "main.rkt"))
+                            "main.rkt"
+                            "util/datetime.rkt"))
  (interaction-eval #:eval the-eval
                    (define connection% (class object% (super-new))))
  (interaction-eval #:eval the-eval

collects/db/scribblings/sql-types.scrbl

@@ -330,6 +330,9 @@ The @tt{DATE}, @tt{TIME} (@tt{WITH TIME ZONE} and without),
 @tt{TIMESTAMP} (@tt{WITH TIME ZONE} and without), and @tt{INTERVAL}
 SQL types are represented by the following structures.
 
+See also @secref["datetime-util"] for more functions on datetime
+values.
+
 @defstruct*[sql-date
             ([year exact-integer?]
              [month (integer-in 0 12)]
@@ -390,39 +393,6 @@ SQL types are represented by the following structures.
  (make-sql-timestamp 1969 12 31 19 0 0 0 #f)]
 ]
 
-@deftogether[[
-@defproc[(sql-datetime->srfi-date [t (or/c sql-date? sql-time? sql-timestamp?)])
-         srfi:date?]
-@defproc[(srfi-date->sql-date [d srfi:date?])
-         sql-date?]
-@defproc[(srfi-date->sql-time [d srfi:date?])
-         sql-time?]
-@defproc[(srfi-date->sql-time-tz [d srfi:date?])
-         sql-time?]
-@defproc[(srfi-date->sql-timestamp [d srfi:date?])
-         sql-timestamp?]
-@defproc[(srfi-date->sql-timestamp-tz [d srfi:date?])
-         sql-timestamp?]]]{
-
-  Converts between this library's date and time values and SRFI 19's
-  date values (see @racketmodname[srfi/19]). SRFI dates store more
-  information than SQL dates and times, so converting a SQL time to a
-  SRFI date, for example, puts zeroes in the year, month, and day
-  fields.
-
-@(examples/results
-  [(sql-datetime->srfi-date
-    (query-value pgc "select time '7:30'"))
-   (sql-datetime->srfi-date (make-sql-time 7 30 0 0 #f))]
-  [(sql-datetime->srfi-date
-    (query-value pgc "select date '25-dec-1980'"))
-   (sql-datetime->srfi-date
-    (make-sql-date 1980 12 25))]
-  [(sql-datetime->srfi-date
-    (query-value pgc "select timestamp 'epoch'"))
-   (sql-datetime->srfi-date (make-sql-timestamp 1970 1 1 0 0 0 0 #f))])
-}
-
 @defstruct*[sql-interval
             ([years exact-integer?]
              [months exact-integer?]
@@ -469,12 +439,6 @@ SQL types are represented by the following structures.
   where the @racket[years] and @racket[months] fields are zero.
 }
 
-@defproc[(sql-day-time-interval->seconds [interval sql-day-time-interval?])
-         rational?]{
-
-  Returns the length of @racket[interval] in seconds.
-}
-
 @defproc[(sql-interval->sql-time [interval sql-interval?]
                                  [failure any/c (lambda () (error ....))])
          any]{

collects/db/scribblings/util.scrbl

@@ -4,13 +4,59 @@
           scribble/struct
           scheme/sandbox
           "config.rkt"
-          (for-label db db/util/geometry db/util/postgresql))
+          (for-label db db/util/datetime db/util/geometry db/util/postgresql))
 
 @title[#:tag "util"]{Utilities}
 
 The bindings described in this section are provided by the specific
 modules below, not by @racketmodname[db] or @racketmodname[db/base].
 
+@;{========================================}
+
+@section[#:tag "datetime-util"]{Datetime Type Utilities}
+
+@defmodule[db/util/datetime]
+
+@deftogether[[
+@defproc[(sql-datetime->srfi-date [t (or/c sql-date? sql-time? sql-timestamp?)])
+         srfi:date?]
+@defproc[(srfi-date->sql-date [d srfi:date?])
+         sql-date?]
+@defproc[(srfi-date->sql-time [d srfi:date?])
+         sql-time?]
+@defproc[(srfi-date->sql-time-tz [d srfi:date?])
+         sql-time?]
+@defproc[(srfi-date->sql-timestamp [d srfi:date?])
+         sql-timestamp?]
+@defproc[(srfi-date->sql-timestamp-tz [d srfi:date?])
+         sql-timestamp?]]]{
+
+  Converts between this library's date and time values and SRFI 19's
+  date values (see @racketmodname[srfi/19]). SRFI dates store more
+  information than SQL dates and times, so converting a SQL time to a
+  SRFI date, for example, puts zeroes in the year, month, and day
+  fields.
+
+@(examples/results
+  [(sql-datetime->srfi-date
+    (query-value pgc "select time '7:30'"))
+   (sql-datetime->srfi-date (make-sql-time 7 30 0 0 #f))]
+  [(sql-datetime->srfi-date
+    (query-value pgc "select date '25-dec-1980'"))
+   (sql-datetime->srfi-date
+    (make-sql-date 1980 12 25))]
+  [(sql-datetime->srfi-date
+    (query-value pgc "select timestamp 'epoch'"))
+   (sql-datetime->srfi-date (make-sql-timestamp 1970 1 1 0 0 0 0 #f))])
+}
+
+@defproc[(sql-day-time-interval->seconds [interval sql-day-time-interval?])
+         rational?]{
+
+  Returns the length of @racket[interval] in seconds.
+}
+
+
 @;{========================================}
 
 @section[#:tag "geometry"]{Geometric Types}

collects/db/util/datetime.rkt

@@ -0,0 +1,84 @@
+#lang racket/base
+(require racket/contract
+         racket/match
+         (prefix-in srfi: srfi/19)
+         "../private/generic/sql-data.rkt")
+
+(define (sql-datetime->srfi-date datetime)
+  (match datetime
+    [(struct sql-date (year month day))
+     (srfi:make-date 0 0 0 0 day month year 0)]
+    [(struct sql-time (hour minute second nanosecond tz))
+     (srfi:make-date nanosecond second minute hour 0 0 0 (or tz 0))]
+    [(struct sql-timestamp (year month day hour minute second nanosecond tz))
+     (srfi:make-date nanosecond second minute hour day month year (or tz 0))]
+    [else
+     (raise-type-error 'sql-datetime->srfi-date
+                       "sql-date, sql-time, or sql-timestamp"
+                       datetime)]))
+
+(define (srfi-date->sql-date date)
+  (make-sql-date (srfi:date-year date)
+                 (srfi:date-month date)
+                 (srfi:date-day date)))
+
+(define (srfi-date->sql-time* date tz? ns)
+  (make-sql-time (srfi:date-hour date)
+                 (srfi:date-minute date)
+                 (srfi:date-second date)
+                 (or ns (srfi:date-nanosecond date))
+                 (and tz? (srfi:date-zone-offset date))))
+
+(define (srfi-date->sql-time date [ns #f])
+  (srfi-date->sql-time* date #f ns))
+
+(define (srfi-date->sql-time-tz date [ns #f])
+  (srfi-date->sql-time* date #t ns))
+
+(define (srfi-date->sql-timestamp* date tz? ns)
+  (make-sql-timestamp (srfi:date-year date)
+                      (srfi:date-month date)
+                      (srfi:date-day date)
+                      (srfi:date-hour date)
+                      (srfi:date-minute date)
+                      (srfi:date-second date)
+                      (or ns (srfi:date-nanosecond date))
+                      (and tz? (srfi:date-zone-offset date))))
+
+(define (srfi-date->sql-timestamp date [ns #f])
+  (srfi-date->sql-timestamp* date #f ns))
+
+(define (srfi-date->sql-timestamp-tz date [ns #f])
+  (srfi-date->sql-timestamp* date #t ns))
+
+(define (sql-day-time-interval->seconds x)
+  (+ (* (sql-interval-hours x) 60 60)
+     (* (sql-interval-minutes x) 60)
+     (sql-interval-seconds x)
+     (/ (sql-interval-nanoseconds x) #i1e9)))
+
+;; ============================================================
+
+;; Note: MySQL allows 0 month, 0 day, etc.
+
+(provide/contract
+ [sql-datetime->srfi-date
+  (-> (or/c sql-date? sql-time? sql-timestamp?)
+      srfi:date?)]
+ [srfi-date->sql-date
+  (-> srfi:date? sql-date?)]
+ [srfi-date->sql-time
+  (->* (srfi:date?) ((or/c exact-nonnegative-integer? #f))
+       sql-time?)]
+ [srfi-date->sql-time-tz
+  (->* (srfi:date?) ((or/c exact-nonnegative-integer? #f))
+       sql-time?)]
+ [srfi-date->sql-timestamp
+  (->* (srfi:date?) ((or/c exact-nonnegative-integer? #f))
+       sql-timestamp?)]
+ [srfi-date->sql-timestamp-tz
+  (->* (srfi:date?) ((or/c exact-nonnegative-integer? #f))
+       sql-timestamp?)]
+
+ [sql-day-time-interval->seconds
+  (-> sql-day-time-interval? rational?)])

collects/tests/db/db/sql-types.rkt

@@ -5,6 +5,7 @@
          racket/string
          (prefix-in srfi: srfi/19)
          db/base
+         db/util/datetime
          db/util/geometry
          db/util/postgresql
          "../config.rkt")

collects/tests/db/gen/sql-types.rkt

@@ -5,6 +5,14 @@
          db/base
          db/private/generic/sql-convert
          "../config.rkt")
+(require/expose
+ db/private/postgresql/dbsystem
+ (parse-date
+  parse-time
+  parse-time-tz
+  parse-timestamp
+  parse-timestamp-tz))
+
 (provide sql-types:test)
 
 (define sql-types:test