MySql::Result#each_hash deletes data

[eagle eyes joe]

Greetings:

You can only read a Mysql::Result object once because
each_key deletes the values as it reads them. This is unexpected and I
think it should be fixed.

This little program shows what I mean:


[Abba:/tmp] josephal% cat resulttest
#!/usr/bin/ruby

require 'mysql'

m = Mysql.new("localhost", "root", "", "Development")

r = m.query("select * from processedfiles limit 5")

r.each_hash { |row| print "#{row['name']}\n" }

print "---------------------------------------\n"

r.each_hash { |row| print "#{row['name']}\n" }

print "------------------- -\nthis is the end\n"


[Abba:/tmp] josephal% resulttest
AD030220
AD030221
AD030228
AD030307
AD000428

 

[Kent Sibilev]

No, this corresponds to the way Mysql C API works. Use
Mysql::Result#row_seek to return to the beginning of the result set.
You shouldn't treat Mysql::Result as a in-memory Enumerable object,
because there are usually resources allocated on the server for each
Mysql::Result instance.

Cheers,
Kent.

 

[eagle eyes joe]

Kent,

Thanks for your help. Are you saying that the data is still there in
the Result object, but I am pointing to the end and I need to rest the
pointer to the beginning? Can you give me an example of using
Result#row_seek?

Thanks again,

Joe.

No, this corresponds to the way Mysql C API works. Use
Mysql::Result#row_seek to return to the beginning of the result set.
You shouldn't treat Mysql::Result as a in-memory Enumerable object,
because there are usually resources allocated on the server for each
Mysql::Result instance.

Cheers,
Kent.

Greetings:

You can only read a Mysql::Result object once because
each_key deletes the values as it reads them. This is unexpected and
I
think it should be fixed.

This little program shows what I mean:


[Abba:/tmp] josephal% cat resulttest
#!/usr/bin/ruby

require 'mysql'

m = Mysql.new("localhost", "root", "", "Development")

r = m.query("select * from processedfiles limit 5")

r.each_hash { |row| print "#{row['name']}\n" }

print "---------------------------------------\n"

r.each_hash { |row| print "#{row['name']}\n" }

print "------------------- -\nthis is the end\n"


[Abba:/tmp] josephal% resulttest
AD030220
AD030221
AD030228
AD030307
AD000428