[REBOL] REBOL Relational Object-oriented Database Ver. 0.4
From: louisaturk:eudoramail at: 26-Jun-2001 19:51
Hi everybody,
Special thanks to Carl, Scott, Holger, Jeff, and everyone else that helped
me with this project.
Below is version 0.4 of the database. Some of my code may be rather crude,
since I am still learning this language, but the code written by the other
contributors looks great (to me at least). Unless there are some bugs I
missed, the program works fine. It is not relational yet, but since it
will be by version 1.0 (I hope) I'm leaving relational in the name to keep
myself motivated to finish it.
PLANNED IMPROVEMENTS (calling all experts for help!):
1. An edit-data function that will display the current data in the field
so that the arrow keys can be used to position the cursor to change just a
letter or so---so that the entire field does not have to be retyped to
correct typos. I hate unnecessary typing! I am hoping that there are
secrets hidden somewhere in REBOL that will make this function easy to write.
2. Relate two or more databases together on key fields so that reports can
be written using data from all the databases.
3. Compress (and encrypt, if possible) the data file as it is being backed up.
4. Would there be any practical advantage to putting a View face on this
program, other than looks? Would using a View interface slow down performance?
If anyone finds any bugs or has suggestions, please let me know! Again,
many thanks to all who have helped me with this!
Sincerely,
Louis
REBOL [
Title: "REBOL Relational Object DBMS"
Date: "26 June 2001"
Version: 0.4
File: %db.r
Author: "Carl Sassenrath, G. Scott Jones, and Louis A. Turk"
Email: [louisaturk--eudoramail--com]
Language: 'English
Purpose: "A simple but complete relational object-oriented dbms."
Comments: {Carl Sassenrath made these object oriented database
management system functions as an example to teach me,
Louis A. Turk, how to program an object database myself.
Many thanks Carl! The comments about features below are
mostly Carl's, edited by Louis for this script header.
Features:
1. The db works from memory. Load-data brings it into memory
where the find, remove and other functions operate on it.
So, you have to load it first, or at least insert-data a
few times to create some data records.
2. You can expand or reduce the record definition without
corrupting or affecting the database.
3. If you expect to grow this database to a large size,
you will want to MAKE HASH! the database when you
load it. make the hash after the database is created
(after the foreach loop).
database: make hash! database
But, don't worry about that until your database gets big.
For a few hundred names, you don't need it.
4. The functions work like this:
rec: find-data [bob--example--com]
print rec/name
print rec/phone
etc.
remove-data [bob--example--com]
save-data ; write back to disk
insert-data [kit--example--com] "Kitty Carson" none http:/www.a.com
save-data ; write back to disk
5. You can use NONE for any missing value above. You don't
need to do the save-data each time... but you must do it
sooner or later.
6. The data is organized (keyed) by email. To change an
email address, but keep the rest of the record intact,
use the function change-data. Let's examine change-data:
change-data: func [email-old email-new /local record] [
record: find database email-old
if none? record [alert reform ["Missing record:"
email-old] exit]
insert clear first record email-new ; see note below
]
Note: This is subtle, so should be noted... I'm clearing
out the actual memory string for the old email, then inserting
the new string into it.
Also, this string is shared. It is used both in the database
block (as the key) and in the record object itself. So changing
it here will change it in both places.
Please send any bug reports or features you add to:
[louisaturk--eudoramail--com]
} ;End of Comments
History: {
26-Jun-2001 Louis A. Turk changed the follow:
1) Corrected a bug that allowed import of duplicate records.
2) Added a List-Dir choice to the main menu to make it easier to
find import files.
3) Added backup and restore utilities.
26-Jun-2001 G. Scott Jones, M.D. changed the following:
1) Added check for existence of data file and check
for empty data file.
2) Commented out hash until fully debugged
3) Changed name of update function for key data from
change-data to update-key-data
4) Added default choice of 0 to avoid initial error
5) Added additional forever loop to allow editing
of multiple fields in edit record section
6) Changed from if construct to switch inside edit record
? whether need to set choice to 0 anymore
7) Changed method for updating no-key fields
8) Added ability to edit key-field email from within edit
record. ? whether need separate email update function.
9) Added checks for empty data on edit/update
10) Reset database to head after forskip (NB: forskip
leaves the series pointer pointing at the tail) in print
section
11) Changed csv import to leave data elements in same
format as "native" data file format (namely, string).
12) Made a few miscellaneous formatting changes, including
recommended REBOL indent
13) Other miscellaneous changes mostly commented in code.
} ; End of History
] ;End of Rebol Script Header
db-file: %data.r
record: context [name: email: phone: web: none] ;Place the none value in
all the varables.
database: copy []
load-data: has [data] [
if exists? db-file [
data: load/all db-file
clear database
if data [
foreach item data [
item: make record item
repend database [item/email item]
]
]
database: make hash! database
]
]
update-key-data: func [email-old email-new /local record] [
record: find database email-old
if none? record [alert reform ["Missing record:" email-old] exit]
insert clear first record email-new ; See note in feature #6 above.
]
; ? whether needed
edit-data: func [field index /local record] [
record: find database field
if none? record [alert reform ["Missing record:" field] exit]
record/index: field
]
save-data: has [data] [
data: copy []
foreach [key obj] database [
append/only data third obj
]
save db-file data
]
find-data: func [email] [select database email]
remove-data: func [email] [remove/part find database email 2]
insert-data: func [email' name' phone' web'] [
repend database [
email'
make record [
email: email'
name: name'
phone: phone'
web: web'
]
]
]
{Holger and Jeff helped me with this function. I changed it some trying to
learn how to use it.}
kbhit: does [
con: open/direct/binary/no-wait console://
until [wait con]
choice: to-char pick con 1
close con
choice
]
;kbhit: does [
; con: open/direct/binary/no-wait console://
; until [wait con]
; first reduce [to-string copy con close con]
;]
{Below is a simple character based user interface for REBOL/Core added by
Louis A. Turk}
load-data
choice: 0 ; to avoid initial error
forever [
cls: "^(1B)[J" ; Clear the Screen.
print cls
print "^/ REBOL RELATIONAL OBJECT-ORIENTED DBMS" ; ^/ is a line feed.
print " =====================================^/"
print " 1. Add Record."
print " 2. Edit a Field In a Record."
print " 3. Delete Record."
print " 4. Change Email Address Only."
print " 5. Print Reports."
print " 6. Export Data To CSV File."
print " 7. Import (APPEND) Data From CSV File."
print " 8. List Current Directory."
print " 9. Backup the Database to Floppy Disk A: "
print " 0. Restore the Database from Floppy Disk A: "
prin "^/ Enter the # of Choice (or ESC to Exit): "
choice = kbhit
;may wish to change this to a switch construct in future
if choice = #"1" [
forever [
print cls
print " ADD A RECORD"
print " ============^/"
email: ask " Email Address: "
if email = "" [break] ;gsj added to avoid empty error
rec: find database email
either rec = none [
name: ask " Full Name: "
phone: ask " Area Code & Phone#: "
web: ask " Website URL: "
insert-data email name phone web
save-data
][
ask "^/ Record is already in database. Continue? "
]
] ; End forever loop for choice 1
] ; End if choice 1
if choice = #"2" [
forever [
print cls
print " EDIT A FIELD IN A RECORD"
print " ========================^/"
email-old: ask " Email Address: "
if email-old = "" [break]
forever [
record: find database email-old
if record = none [
print cls
print "^/ Missing record: " email-old
ask "^/ Hit Any Key To Continue."
break
]
record: find-data email-old
print ["^/ 1. Email : " record/email]
print [" 2. Name : " record/name]
print [" 3. Phone : " record/phone]
print [" 4. URL : " record/web]
print [" 5. Return to Edit Menu" "^/"]
prin [" Enter number of field to change: "]
choice: kbhit
; I'm using this method of accessing fields since records
in databases
; to be expanded from this one may have 10 to 30 fields
with only
; one usually needing editing.
switch/default choice [
#"1" [
print cls
print " EDIT EMAIL ADDRESS"
print " ==================^/"
email-new: ask rejoin [" New Email Address to
replace " email-old ": "]
if email-new <> "" [
update-key-data email-old email-new
save-data
email-old: copy email-new
]
choice: "0" ; Added this hack to solve a logic
problem.
]
#"2" [
print cls
print " CHANGE NAME"
print " ===========^/"
new-name: ask rejoin ["Enter name to replace "
record/name ": "]
if new-name <> "" [record/name: copy new-name
save-data]
choice: "0"
]
#"3" [
print cls
print " CHANGE PHONE"
print " ===========^/"
new-phone: ask rejoin ["Enter phone to replace "
record/phone ": "]
if new-phone <> "" [record/phone: copy new-phone
save-data]
choice: "0"
]
#"4" [
print cls
print " CHANGE URL"
print " ===========^/"
new-url: ask rejoin ["Enter url to replace "
record/web ": "]
if new-url <> "" [record/web: copy new-url save-data]
choice: "0"
]
][break] ;end of switch and switch/default
] ; end of forever for editing a record
] ; End forever loop
] ; End if choice 2
if choice = #"3" [
forever [
print cls
print " DELETE A RECORD"
print " ===============^/"
email-old: ask " Email Address Of Record To Delete: "
;if email-old = "" [
; break
;] ; End if.
record: find database email-old
if none? record [
print cls
print " Record not found.^/"
ask " Hit Any Key To Continue."
break
]
remove-data email-old
save-data
] ; End forever loop for choice 3.
] ; End if choice 3
if choice = #"4" [
forever [
print cls
print " CHANGE EMAIL ADDRESS ONLY"
print " ==========================^/"
email-old: ask " Email Address To Be Changed: "
if email-old = "" [break]
record: find database email-old
if none? record [
print cls
print "Missing record: " email-old
ask "Hit Any Key To Continue."
break
]
email-new: ask rejoin [" New Email Address to replace "
email-old ": "]
if email-new <> "" [
update-key-data email-old email-new
save-data
]
] ; End forever loop for choice 4
] ; End if choice 4
{Scott Jones provided the core code for choices 4, 5, and 6 below.}
if choice = #"5" [
print cls
print " PRINT FORMATTED REPORTS"
print " ======================="
forskip database 2 [
print ["^/ Email: " database/2/email]
print [" Name: " database/2/name]
print [" Phone: " database/2/phone]
print ["Web URL: " database/2/web]
]
prin "^/Press any key to continue..."
database: head database ;reset following forskip
kbhit
]
if choice = #"6" [
print cls
print " EXPORT DATA TO CSV FILE"
print " =======================^/"
csv: ask "Name of CSV File to Write to: "
either not csv = "" [
csv-file: to-file csv
write csv-file "" ;to get fresh file
emit: func [blk] [repend csv-line blk]
forskip database 2 [
csv-line: make string! 1000
emit [{"} database/2/email {","} database/2/name {","}
database/2/phone
{","} database/2/web {"^/}]
write/append csv-file csv-line
]
database: head database ;reset following forskip
prin "^/The file has been written. Continue? "
kbhit
][prin "^/You forget to enter a file name. Continue? " kbhit]
]
if choice = #"7" [
print cls
csv: ask "Name of CSV File to Read From: "
either not csv = "" [
csv-file: to-file csv
data: read/lines csv-file
foreach line data [
foreach [email name phone web] parse line none [
email: trim email
name: trim name
phone: trim phone
web: trim web
if not find database email [insert-data email name
phone web]
save-data
]
]
prin "^/The Data Has Been Appended to the
Database. Continue? "
kbhit
][prin "^/You forget to enter a file name. Continue? " kbhit]
]
if choice = #"
