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From redshift-etl-user <redshift....@gmail.com>
Subject Re: Null values and escaping
Date Sun, 05 Jan 2014 02:06:56 GMT
Abe,

Sure - the problem is that whatever I specify as the null-string, say X, I
don't see how I can distinguish between that X and an actual string X in
the resulting text file. Any ideas?

Thanks.
On Jan 4, 2014 1:47 AM, "Abraham Elmahrek" <abe@cloudera.com> wrote:

> Hey There,
>
> Have you tried the --null-string option? See
> http://sqoop.apache.org/docs/1.4.4/SqoopUserGuide.html#idp3491496 for
> more details. It should change null string values to what ever string you
> specify.
>
> -Abe
>
>
> On Fri, Jan 3, 2014 at 4:34 AM, redshift-etl-user <redshift.etl@gmail.com>wrote:
>
>> I'm importing from a DB into a text file, and I need to distinguish
>> between null and non-null strings. Is there a combination of parameters
>> (i.e. escaped-by, enclosed-by, and null-string) that yields unambiguous
>> output strings? With the default options "null-string" is "null", and so
>> there's no way of distinguishing between a null string and the string
>> "null" in the output file.
>>
>> One solution to this would be to avoid escaping the specified null
>> string. That way we could specify "escaped-by" as "\" and "null-string" as
>> "\N" and get "\N" in the output as opposed to "\\N" for null strings. That
>> way it's guaranteed to be different from any non-null string.
>>
>> In the generated code's toString() method this would mean changing from
>>
>> __sb.append(FieldFormatter.escapeAndEnclose(STRING==null?"\\N":STRING,
>> delimiters));
>>
>> to
>>
>> __sb.append(STRING==null?"\\N":FieldFormatter.escapeAndEnclose(STRING,
>> delimiters));
>>
>> Thoughts? Any ideas for a workaround?
>>
>>  Thanks!
>>
>
>

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