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comp.lang.ruby

sqlite3-ruby problem accessing row values

The Doobs

6/20/2008 8:31:00 PM

I get a "can't convert String into Integer (TypeError)" error about the
print statement in the following code. The sqlite3-ruby library has been
installed successfully on my OS X 10.5 system. The code executes fine if
I replace the print statement with: print "hello". Any suggestions? All
I want to do is iterate through each row in the return set (rows) of the
executed query and look at specific column values. I have run out of
ideas on how to fix this and would appreciate any help. Thanks...

#!/usr/bin/ruby

require "sqlite3"

query = "select * from moz_bookmarks"
db = SQLite3::Database.new("/Users/me/Desktop/places.sqlite")
rows = db.execute(query)
rows.each do |row|
print row['title']
end
--
Posted via http://www.ruby-....
6 Answers

Bryan JJ Buckley

6/21/2008 9:16:00 AM

0

2008/6/20 The Doobs <thedoobs@gmail.com>:
> I get a "can't convert String into Integer (TypeError)" error about the
> print statement in the following code. The sqlite3-ruby library has been
> installed successfully on my OS X 10.5 system. The code executes fine if
> I replace the print statement with: print "hello". Any suggestions? All
> I want to do is iterate through each row in the return set (rows) of the
> executed query and look at specific column values. I have run out of
> ideas on how to fix this and would appreciate any help. Thanks...
>
> #!/usr/bin/ruby
>
> require "sqlite3"
>
> query = "select * from moz_bookmarks"
> db = SQLite3::Database.new("/Users/me/Desktop/places.sqlite")
> rows = db.execute(query)
# Rows is an array of arrays....
> rows.each do |row|
# At this point, "row" is a straightforward array - you need to use
Integer indices
> print row['title']
# This fails because you cannot use a string as an integer into an array. Try
puts row[0]
> end
> --
> Posted via http://www.ruby-....
>
>


--
JJ

Leslie Viljoen

6/21/2008 9:19:00 AM

0

On 6/20/08, The Doobs <thedoobs@gmail.com> wrote:
> I get a "can't convert String into Integer (TypeError)" error about the
> print statement in the following code. The sqlite3-ruby library has been
> installed successfully on my OS X 10.5 system. The code executes fine if
> I replace the print statement with: print "hello". Any suggestions? All
> I want to do is iterate through each row in the return set (rows) of the
> executed query and look at specific column values. I have run out of
> ideas on how to fix this and would appreciate any help. Thanks...
>
> #!/usr/bin/ruby
>
> require "sqlite3"
>
> query = "select * from moz_bookmarks"
> db = SQLite3::Database.new("/Users/me/Desktop/places.sqlite")
> rows = db.execute(query)
> rows.each do |row|
> print row['title']
> end

Perhaps it would help if you uploaded places.sqlite somewhere (like
Mediafire) so we can try the program. Otherwise, even the schema would
help

Les

Leslie Viljoen

6/21/2008 9:23:00 AM

0

On 6/21/08, Leslie Viljoen <leslieviljoen@gmail.com> wrote:
> On 6/20/08, The Doobs <thedoobs@gmail.com> wrote:
> > I get a "can't convert String into Integer (TypeError)" error about the
> > print statement in the following code. The sqlite3-ruby library has been
> > installed successfully on my OS X 10.5 system. The code executes fine if
> > I replace the print statement with: print "hello". Any suggestions? All
> > I want to do is iterate through each row in the return set (rows) of the
> > executed query and look at specific column values. I have run out of
> > ideas on how to fix this and would appreciate any help. Thanks...
> >
> > #!/usr/bin/ruby
> >
> > require "sqlite3"
> >
> > query = "select * from moz_bookmarks"
> > db = SQLite3::Database.new("/Users/me/Desktop/places.sqlite")
> > rows = db.execute(query)
> > rows.each do |row|
> > print row['title']
> > end
>
>
> Perhaps it would help if you uploaded places.sqlite somewhere (like
> Mediafire) so we can try the program. Otherwise, even the schema would
> help

Nevermind, it's easy to create such a database.

Les

Leslie Viljoen

6/21/2008 9:51:00 AM

0

This program gives what you want:

#!/usr/bin/ruby

require "sqlite3"

query = "select * from moz_bookmarks"
db = SQLite3::Database.new("test.sqlite")
db.results_as_hash = true
rows = db.execute(query)
rows.each do |row|
#p row
#puts row.class
#p row.methods
puts row['title']
end


The commented bits will help you with debugging in the future. They enable
you to see what kind of objects you are dealing with.

The answer to selecting rows by column name is to use
db.results_as_hash as above. This was easily discovered via google.

Go here: http://sqlite-ruby.ruby...
Click on the 'FAQ' link.

Les

The Doobs

6/21/2008 4:48:00 PM

0

Bryan JJ Buckley wrote:
> 2008/6/20 The Doobs <thedoobs@gmail.com>:
>> require "sqlite3"
>>
>> query = "select * from moz_bookmarks"
>> db = SQLite3::Database.new("/Users/me/Desktop/places.sqlite")
>> rows = db.execute(query)
> # Rows is an array of arrays....
>> rows.each do |row|
> # At this point, "row" is a straightforward array - you need to use
> Integer indices
>> print row['title']
> # This fails because you cannot use a string as an integer into an
> array. Try
> puts row[0]

Using integer indices did the trick. Thanks! I was trying to use the
column name 'title'. By the way, the places.sqlite file is the file
where Firefox 3 stores its bookmarks and some other stuff. On OS X, it
can be found in ~/Library/Application
Support/Firefox/Profiles/*.default/.
--
Posted via http://www.ruby-....

Bryan JJ Buckley

6/21/2008 5:01:00 PM

0

You're welcome. :)
@leslie - cool, I didn't know about the results_as_hash, very handy.

--
JJ