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In the original table in sql server,column flag was 'NULL', when i extract data from this table via talend ,and write it into delimited file , it values '',blank. How can i keep the column flag the same as 'NULL'? Except using tReplace.
Can you please test it is null or empty on column flag as 'NULL' after you read from table? For example:
System.out.println("it is null");
System.out.println("it is empty");
Let me know your test result!
Yes, I have tested that already. If I write the data into delimited file first,and then write it to database,it is still empty. If I write it into table directly from one database to another,it is ok,with the ‘NULL’ Value. But,the table has mass data,and if i process it without delimited file ,it may lead to outofmemory exception and low efficency.
Don't know why you use a demited file, but you can convert empty to null on tMap after read it from demilted file, eg:
Thank you shong and janhess
another problem,If the project that i shall do contains a lot of data(more than10,000,000 rows),how can i avoid the outofmemory exception? now we take the way of storing the data into files first ,and then reading data from file on disk . It seems to work fine,except a little slow. Is there any other better ways?
there will be several jobs running parallelly,so we must take care of the memory.