I have three Excel files and one database connection which I need to append as a part of my flow. All four datasets in the pre-append stage have just one column.
When I try to use tUnite, I get the error for tFileInputExcel - see the screenshot. Moreover, I cannot join the database connection with tUnite.
What am I doing wrong?
I think the problem is with the tFileExist components (I think that's what these are on the left with the "if" links coming out) because each of them is trying to start a new flow. Once you're joining them with the unite, there can be only one start to the flow - and this goes to the start of the first branch of the merge order.
You can move the if logic elsewhere. Another idea is to put the output from each of the Excel into a tHashOutput (linked together), then use a tHashInput to write to your DB.
Related
I want to take data from 2 databases and copy(coalesce) it into 1 using Data factory.
The issue is: It seems that multiple inputs is not allowed for copy activities.
So i resorted to having 2 different datasets which are exact copies but with a different name... and then putting 2 different activities into the 1 pipeline which use their specific output dataset.
It just seems odd and wrong to do it this way.
Can i have some help.
This is what my diagram currently looks like:
Is there no way of just copying data from 2 seperate databases (which have the same structure but different data) to the 1 database?
The short answer is yes. But you need to work within the constraints of how ADF handles this.
A couple of things to help...
You'll always need at least 2 activities to do this when using the copy type activity. Microsoft of course charges per activity execution in ADF, so they aren't going to allow you to take shortcuts having many inputs and output per single copy activity (single charge).
The approach you show above is ok and to pass the ADF validation as you've found you simply need to have the output datasets created separately and called different things. Even if they still refer to the same underlying target table etc. This is really only a problem for the copy activity. What you could do is land the data firstly into separate staging tables in the Azure target database just for the copy (1:1). Then have a third downstream activity that executes a stored procedure that does the union of tables. In this case you could have 2 inputs to 1 output in the activity if you want to have that level of control in ADF.
Like this:
Final point, if you don't want the activities to execute in parallel you could chain the datasets to enforce a fake dependency or add a simple 'delay' clause to one of the copy operations. A delay on an activity would be simpler than provisioning a time slice offset.
Hope this helps
I have a number of excel files where there is a line of text (and blank row) above the header row for the table.
What would be the best way to process the file so I can extract the text from that row AND include it as a column when appending multiple files? Is it possible without having to process each file twice?
Example
This file was created on machine A on 01/02/2013
Task|Quantity|ErrorRate
0102|4550|6 per minute
0103|4004|5 per minute
And end up with the data from multiple similar files
Task|Quantity|ErrorRate|Machine|Date
0102|4550|6 per minute|machine A|01/02/2013
0103|4004|5 per minute|machine A|01/02/2013
0467|1264|2 per minute|machine D|02/02/2013
I put together a small, crude sample of how it can be done. I call it crude because a. it is not dynamic, you can add more files to process but you need to know how many files in advance of building your job, and b. it shows the basic concept, but would require more work to suite your needs. For example, in my test files I simply have "MachineA" or "MachineB" in the first line. You will need to parse that data out to obtain the machine name and the date.
But here is how may sample works. Each Excel is setup as two inputs. For the header the tFileInput_Excel is configured to read only the first line while the body tFileInput_Excel is configured to start reading at line 4.
In the tMap they are combined (not joined) into the output schema. This is done for the Machine A Excel and Machine B excels, then those tMaps are combined with a tUnite for the final output.
As you can see in the log row the data is combined and includes the header info.
I'm wondering how to increment a number "extracted" from a field in a csv, and then rewrite the file with the number incremented.
I need this counter in a tMap.
Is the design below a good way to do it ?
EDIT: im trying a new method. see the design of my subjob below, but i have an error when i link the tjavarow to my main tmap in the main job
Exception in component tMap_1
java.lang.NullPointerException
at mod_file_02.file_02_0_1.FILE_02.tFileList_1Process(FILE_02.java:9157)
at mod_file_02.file_02_0_1.FILE_02.tRowGenerator_5Process(FILE_02.java:8226)
at mod_file_02.file_02_0_1.FILE_02.tFileInputDelimited_2Process(FILE_02.java:7340)
at mod_file_02.file_02_0_1.FILE_02.runJobInTOS(FILE_02.java:12170)
at mod_file_02.file_02_0_1.FILE_02.main(FILE_02.java:11954)
2014-08-07 12:43:35|bm9aSI|bm9aSI|bm9aSI|MOD_FILE_02|FILE_02|Default|6|Java
Exception|tMap_1|java.lang.NullPointerException:null|1
[statistics] disconnected
enter image description here
You should be able to do this mid flow in a tMap or a tJavaRow.
Simply read the number in as an integer (or other numeric data type) and then add your increment to it.
A really simple example might look like this:
Here we have a tFixedFlowInput that has some hard coded values for the job:
And we run it through a tMap where we add 1 to the age column:
And finally, we output it to the console in a table:
EDIT:
As Gabriele B has pointed out, this doesn't exactly work when reading and writing to the same flat file as Talend claims an exclusive read-write lock on the file when reading and keeps it open throughout the job.
Instead you would have to write the incremented data to some other place such as a temporary file, a database or even just to the buffer and then read that data in to a separate job which would then output the file you want and clean up anything temporary.
The problem with that is you can't do the output in the same process. I've just tried testing reading in the file in one child job, passing the data back to a parent job using a tBufferOutput and then passing that data to another child job as a context variable and then trying to output to the file. Unfortunately the file lock remains on it so you can't do this all in one self contain job (even using a parent job and several child jobs).
If this sounds horrible to you (it is) and you absolutely need this to happen (I'd suggest a database table sounds like a better match for this functionality than a flat file) then you could raise a feature request on the Talend Jira for the tFileInputDelimited to not hold the file open or to not insist on an exclusive read-write lock on the file.
Once again, I strongly recommend that you move to using a database table for this because even without the file lock issue, this is definitely not the right use of a flat file and this use case perfectly fits a database, even something as lightweight as an embedded H2 database.
I tried to display some results from several files in a directory. I use TFileList, and 2 tFileInputDelimited which are both linked to TFileList. I don't know why but at the end of the processing my results are lugged from just one of the 6 files I want. It appears that there are results from the list file of the directory.
Each tFileInputDelimited has ((String)globalMap.get("tFileList_1_CURRENT_FILEPATH")) as name of the flow.
Here is my TMap:
Your job is set up so your lookup is iterative which causes some issues as Talend only seems to use the last iteration rather than doing what you might expect and iterating through every step for everything it needs (although this might be more complicated than you first think).
One option is to rework the job so you use your iterate part of the job as the main input to the tMap rather than the lookup.
Alternatively, you could iterate the data into a tBufferOutput component and then OnSubjobOk you could link the job as before but replace the iterative part with a tBufferInput component as it will store all of the data from all of the files iterated through.
I'm looking for a way how to split job execution in talend studio according to actual file row - I'd like to process file rows starting with "DEBUG" in one job branch and another rows in another job branch. It that possible?
To do this, use a tMap component. Your job will look like this
t*Input--row-->tMap--out1--->tFileOutput*
--out2--->tFileOutput*
In the tMap component, you have input on the left and output on the right. In your output table, select "Activate expression filter" and use the text box to define your filter-- only rows that match that filter will be ouput from that connection. You can have as many output tables and filters as you need.
Using tMap is cool, but if number of output stream is not defined and fixed, tMap is not a good choice.
In this case using iterate link or tjavaflex can help you:
Have a look at this tutorial on "how to split a file into many files regarding a key on each record" which explains how to solve this kind of task. It is actually only available in french. The tutorial shows 3 different technics to achieve this task.
Finally I used tExctractRegeFields component - simply defined regex for matching lines. The most important (and I didn't know before) is that you can connect components with different types of connections. I did right click on used component a chose Row > Reject for new branch in job as described in question.
We can do it by using tfileoutputdelimited and tfileinputdelimited.
We have one option in tfileoutputdelimited in advanced settings and check option split out files in several files.