[REBOL] RWT: db-logic
From: maarten::koopmans::surfnet::nl at: 3-Mar-2003 19:45
REBOL []
; Anonymous context for database functions.
context
[
; Stuff that could be moved out of this script
database-scheme: "mysql"
database-connect-retries: 5
dbport: none
cmdport: none
sql-reduce: func
[
{Reduces a REBOL value to it's SQL representation}
val
/local sql-val
]
[
either any [ integer? val decimal? val ]
[
sql-val: to string! val
]
[
sql-val: copy {'}
append sql-val either date? val
[
format-date val
]
[
replace to string! val {'} {''}
]
append sql-val {'}
]
return sql-val
]
reduce-query: func
[
{Reduces a block query to its string equivalent. The block query
contains a template portion with ? characters at the places where
values need to be filled in.}
bl [block!] {Block containing the template and the values to fill in.}
/local template dummy-char reduced-block
]
[
dummy-char: to char! 0
reduced-block: reduce bl
template: to string! first reduced-block
foreach val next reduced-block
[
if found? find template "?"
[ replace template "?" replace/all sql-reduce val #"?" dummy-char ]
]
return replace/all template dummy-char #"?"
]
format-date: func
[
{Formats a date as a string suitable for use with the database.}
time [date!]
]
[
return rejoin [ time/year {-} time/month {-}
time/day { } either time/time [ time/time ][ {00:00:00} ] ]
]
system/words/init-db: func
[
{Initializes the database connection if it is not already open.}
[catch]
/local err
]
[
; Only init the connection if it is not yet open.
if dbport [ return true ]
loop database-connect-retries
[
if error? set/any 'err try
[
dbport: open database-url
if dbport
[
cmdport: dbport
insert cmdport "set autocommit=0"
return true
]
]
[
err: disarm err
]
]
throw make error! join {Unable to open database connection: } mold err
]
system/words/close-db: func
[
{Closes the database connection if it is open.}
]
[
if cmdport [ close cmdport ]
;if dbport [ close dbport ]
dbport: none
cmdport: none
]
system/words/query-db: func
[
{Sends a query to the database server for execution. If the statement
contains a 'select' statement, the results are returned.}
[catch]
statement [block! string!] {The statement to execute.}
/local data
]
[
if not dbport
[
throw make error! "*** Database port is not open!"
]
;insert cmdport either block? statement
; [ reduce-query statement ]
; [ statement ]
insert cmdport statement
if find mold statement "select"
[
data: copy cmdport
return either data [ data ] [ copy [] ]
]
]
]
