OpenEuphoria

1. Problem with mydata.ex

• Posted by davidmosley Feb 21, 2010
• 1104 views

Hi I have a problem with mydata.ex,When i changed the fields and then i ran the program,i add a record,then i tried to list all records i get a error in the show procedure see below: I can not firure out why,can you help thanks David Mosley davidpmosley@gmail.com

error file:

C:\euphoria\DEMO\mydata.ex:86 in procedure show()  
subscript value 4 is out of bounds, reading from a sequence of length 3  
    f = 1 
    key = {53'5',48'0',53'5',51'3',50'2',53'5',53'5',53'5',56'8',53'5'} 
    data = { 
             {77'M',111'o',115's',108'l',101'e',121'y'}, 
             {68'D',97'a',118'v',105'i',100'd'}, 
             {80'P'} 
           } 
    i = 5 
 
... called from C:\euphoria\DEMO\mydata.ex:162 in procedure list()   
    f = 1 
    rec = 2 
 
... called from C:\euphoria\DEMO\mydata.ex:205 in procedure main()   
    command = {76'L'} 
    printer = <no value> 
 
... called from C:\euphoria\DEMO\mydata.ex:222  
 
 
Global & Local Variables 
 
 c:\euphoria\include\machine.e: 
    mem = 46013088 
    check_calls = 1 
 
 c:\euphoria\include\misc.e: 
    pretty_end_col = <no value> 
    pretty_chars = <no value> 
    pretty_start_col = <no value> 
    pretty_level = <no value> 
    pretty_file = <no value> 
    pretty_ascii = <no value> 
    pretty_indent = <no value> 
    pretty_ascii_min = <no value> 
    pretty_ascii_max = <no value> 
    pretty_line_count = <no value> 
    pretty_line_max = <no value> 
    pretty_dots = <no value> 
    pretty_fp_format = <no value> 
    pretty_int_format = <no value> 
    pretty_line = <no value> 
 
 c:\euphoria\include\file.e: 
    SLASH = 92'\' 
    my_dir = -2 
 
 c:\euphoria\include\get.e: 
    input_file = <no value> 
    input_string = <no value> 
    string_next = <no value> 
    ch = <no value> 
 
 c:\euphoria\include\database.e: 
    current_db = 3 
    current_table = 23 
    db_names = { 
                 {109'm',121'y',100'd',97'a',116't',97'a',46'.',101'e',100'd', 
98'b'} 
               } 
    db_file_nums = {3} 
    db_lock_methods = {0} 
    current_lock = 0 
    SLASH_CHAR = {92'\',47'/'} 
    key_pointers = {620,481} 
    db_fatal_id = 0 
    mem0 = 46013104 
    mem1 = 46013105 
    mem2 = 46013106 
    mem3 = 46013107 
    memseq = {46013104,4} 

Mydata.ex

----------------------- Simple Customizable Database ----------------------- 
 
-- This program uses the Euphoria Database System (EDS) to create and 
-- maintain a simple database. You can customize this program by modifying 
-- the FIELDS variable (below). You'll have to delete or rename the  
-- "mydata.edb" database file if you change the number of fields. 
 
constant FIELDS = { 
   -- The first field is the "key" value used for lookups, 
   -- and it must only occur in one record. We used the phone number 
   -- (like our local dry cleaner does).  
   -- You might want to use the surname, or invent a "person number" 
   -- as an artificial but unique key. 
	"Phone number", 
   -- The other fields can be whatever you like. Feel free to change 
   -- or add more fields... 
	"Last Name", 
	"First name", 
	"Middle Initial", 
	"Address", 
	"City", 
	"State", 
	"Zip", 
	"Email", 
	"Web Site" 
	} 
 
-- file to store the database in: 
constant MYNAME   = "mydata.edb" 
 
include database.e  -- Euphoria Database System 
include get.e 
include sort.e 
include wildcard.e 
 
constant KEYBOARD = 0, 
	 SCREEN   = 1, 
	 ERROR    = 2 
 
constant TRUE = 1 
constant WHITE_SPACE = " \t\n" 
constant FORM_FEED = 12 
 
type file_number(integer x) 
-- document which vars are used as file numbers  
    return x >= 0 
end type 
 
procedure myfatal(sequence msg) 
-- fatal error 
    puts(ERROR, '\n' & "An unexpected error occurred: " & msg & '\n') 
    ? 1/0 -- too see call stack 
end procedure 
 
function user_input() 
-- get user input from keyboard 
    object line 
 
    while TRUE do 
	line = gets(KEYBOARD) 
	if sequence(line) then 
	    -- delete any leading whitespace 
	    while find(line[1], WHITE_SPACE) do 
		line = line[2..length(line)] 
		if length(line) = 0 then 
		    exit 
		end if 
	    end while 
	    if length(line) > 0 then 
		exit 
	    end if 
	end if 
	puts(SCREEN, "\n? ") 
    end while 
    -- delete trailing whitespace 
    while find(line[length(line)], WHITE_SPACE) do 
	line = line[1..length(line)-1]  
    end while 
    return line 
end function 
 
procedure show(file_number f, object key, object data) 
    puts(f, "\n" & key & '\n') 
    -- changed for i = 2 to 1 
    for i = 2 to length(FIELDS) do 
	puts(f, '\t' & data[i-1] & '\n') 
    end for 
end procedure 
 
procedure add() 
-- add a new record to the database 
    sequence key, data 
    integer f 
     
    puts(SCREEN, "\n\t" & FIELDS[1] & ": ") 
    key = user_input() 
    f = db_find_key(key) 
    if f >= 1 then 
	show(SCREEN, db_record_key(f), db_record_data(f)) 
	puts(SCREEN, "Do you want to update this record? (y/n) ") 
	if find('n', gets(0)) then 
	    return 
	end if 
    end if 
    data = {} 
    for i = 2 to length(FIELDS) do 
	puts(SCREEN, "\n\t" & FIELDS[i] & ": ") 
	data = append(data, user_input()) 
    end for 
    puts(SCREEN, '\n') 
    if f >= 1 then 
	-- update data part of record 
	db_replace_data(f, data) 
    else 
	-- insert new record 
	if db_insert(key, data) != DB_OK then 
	    myfatal("insert failed!\n") 
	end if 
    end if 
end procedure  
 
procedure delete() 
-- delete a record, given first field  
    sequence name 
    integer d 
 
    puts(SCREEN, "\n\t" & FIELDS[1] & ": ") 
    name = user_input() 
    d = db_find_key(name) 
    if d < 0 then 
	puts(SCREEN, "\n\tnot found\n") 
	return 
    end if  
    show(SCREEN, db_record_key(d), db_record_data(d)) 
    puts(SCREEN, "Delete? (y/n) ") 
    if find('n', gets(0)) then 
	return 
    end if 
    db_delete_record(d) 
end procedure 
 
procedure find_name() 
-- find the record that matches the surname 
    sequence name 
    integer f 
 
    puts(SCREEN, "\n\t" & FIELDS[1] & ": ") 
    name = user_input() 
    f = db_find_key(name) 
    if f < 0 then 
	puts(SCREEN, "\n\tnot found\n") 
	return 
    end if  
    show(SCREEN, db_record_key(f), db_record_data(f)) 
end procedure 
 
procedure list(file_number f) 
-- list the entire database to a device 
    puts(f, '\n') 
    for rec = 1 to db_table_size() do 
    -- changed f to screen 
	show(f, db_record_key(rec), db_record_data(rec))  
    end for 
end procedure 
 
procedure main() 
    sequence command 
    file_number printer 
     
    -- open or create the database 
    if db_open(MYNAME, DB_LOCK_NO) != DB_OK then 
	if db_create(MYNAME, DB_LOCK_NO) != DB_OK then 
	    myfatal("Couldn't create database") 
	end if 
	if db_create_table("phone numbers") != DB_OK then 
	    myfatal("couldn't create table") 
	end if 
    end if 
 
    -- select the (only) table in the database 
    if db_select_table("phone numbers") != DB_OK then 
	myfatal("couldn't select table\n") 
    end if 
     
    -- prompt the user for his command 
    clear_screen() 
    puts(SCREEN, "\t\tSimple Database\n") 
    while TRUE do 
	puts(SCREEN,  
	     "\n(a)dd, (d)elete, (f)ind, (l)ist, (p)rint, (q)uit: ") 
	command = upper(user_input()) 
	if 'A' = command[1] then 
	    add() 
 
	elsif 'D' = command[1] then 
	    delete() 
 
	elsif 'F' = command[1] then 
	    find_name() 
 
	elsif 'Q' = command[1] then 
	    exit 
 
	elsif 'L' = command[1] then 
	    list(SCREEN) 
 
	elsif 'P' = command[1] then 
	    printer = open("PRN", "w") 
	    if printer = -1 then 
		puts(SCREEN, "Can't open printer device\n") 
	    else 
		list(printer) 
		puts(printer, FORM_FEED) 
		close(printer) 
	    end if 
	else 
	    puts(SCREEN, "\nsay what?\n")                    
	end if  
    end while 
end procedure 
 
main() 

[reformatted with console and eucode tags..matt]

3. Re: Problem with mydata.ex

• Posted by ChrisB (moderator) Feb 21, 2010
• 1067 views
• Last edited Feb 22, 2010

Hi

In line 86 the for loop is counting through the number of FIELDS, which has already been defined at the top of the program.

The number of items in the data variable is less than the number of items in the FIELDS variable.

The loop continues counting the FIELDS items, but exceeds the number of data items, hence throwingthe variable.

Cursorally (?) the correct way would be

    for i = 2 to length(data) do  
	puts(f, '\t' & data[i-1] & '\n')  
    end for 

However, this is only a very cursory look, and this may still not fit your requirements.

Chris

5. Re: Problem with mydata.ex

• Posted by ChrisB (moderator) Feb 23, 2010
• 1008 views

Hi

And it will continue to do so until length(data) > length(FIELDS)

Chris