Rails Migration - Integer Column only contains values of '1'

Question

In a rails project, we are attempting to migrate data from one table to another. When we create the original table, we use (snippet):

create_table :my_original_table do |t|
  #OTHER COLUMNS HERE
  t.integer :first_record_pub
end

Then, when we create the second table to migrate to, we use:

create_table :my_second_table do |t|
  #OTHER COLUMNS HERE
  t.integer :my_pub
end

and finally, when we migrate the actual data, we use:

original_value = MyOriginalTable.all
original_value.each do |s|
  new_first_record = MySecondTable.new
  #OTHER DATA MIGRATIONS HERE
  new_first_record.my_pub = s.first_record_pub
  new_first_record.save
end

All of the other columns that we migrate (the ones I commented out) migrate perfectly. However, in the migrated my_second_table, the my_pub column has some entries that are blank (expected, as some entries in the original table are blank), and the other entries simply have a value of '1'. The correct first_record_pub value was not correctly migrated over, for some reason.

Does anyone have any ideas as how to solve this issue? Thanks!

Try outputting the result of s.inspect to verify that it actually has a first_record_pub that isn't 1. Also try outputting the result of new_first_record after you assign the my_pub value to verify that it was set to what s's first_record_pub is. Just a small sanity check, but it can help point you in the right direction. — MrDanA
– MrDanA, Commented Jul 24, 2012 at 16:34
@MrDanA How do I output the results of s.inspect in the migration? What code should I use? Thank you very much. — dwmcc
– dwmcc, Commented Jul 25, 2012 at 19:41
If you just type puts s.inspect or (short cut) p s then you will get that information outputted to your console when you try to run your migration. — MrDanA
– MrDanA, Commented Jul 25, 2012 at 19:45
@MrDanA - I put 'puts s.inspect' and I receive a list of all the database values coming over from the first table. Oddly enough, the first_record_pub values are coming over and reading correctly! Those without values are coming over as nil (as they should I think), and those that have values in the s.inspect statement have the correct values and those in the new_first_record.inspect statement are turned into 1s. This is ridiculous! Any ideas?! — dwmcc
– dwmcc, Commented Jul 25, 2012 at 20:04

jefflunt · Accepted Answer · 2012-07-24 16:01:26Z

1

Are you both creating a new column, and trying to move data into that column in the same migration? If so you, may either need to make a call to reset_column_information between creating the column and moving data to it, OR, separate the creation and moving of data into two separate migrations.

answered Jul 24, 2012 at 16:01

jefflunt

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5 Comments

dwmcc Over a year ago

No, all three statements above are in separate migrations. Any other ideas? Thanks.

jefflunt Over a year ago

So, the validations aren't failing, correct? So, if you were to change new_first_record.save to new_first_record.save! the migration still runs without aborting, correct?

jefflunt Over a year ago

Do you have mismatched column types? For example, are you copying data from a boolean to an integer column (or some other cross-column type where data might be dropped)? I mean, I can see your pseudo code above and that is uses integer in both places, but have you double-checked the /actual/ code to confirm it's not something like this?

dwmcc Over a year ago

Yes, it doesn't fail, but puts the wrong numbers in the field. And I already checked the column types - all are integer. Thanks

jefflunt Over a year ago

Not sure. I would recommend responding to MrDanA's suggestion in his comment to make sure the migration passes the sanity check, and possibly posting your actual migration code. Maybe there's something in the commented-out code that's inadvertently modifying something in the middle.

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