Good day,
I have component tFileInputRegex and tFlowToIterate to read data from a text file, I saw there are number of row record being process as follow:
Which is 3412 rows, may I know how can I get this value in tJava_2 ?
currently I am using _NB_LINE but getting null:
System.out.println("total is " + (Integer)globalMap.get("tFileInputRegex_1_NB_LINE"));
System.out.println("total2 is " + (Integer)globalMap.get("tFlowToIterate_2_NB_LINE"));
In your example, tJava_2 executes within the iteration, i.e. once for each row. In that component, you can use globalMap.get("tFlowToIterate_2_CURRENT_ITERATION").toString() to get the number of rows processed so far. Please note that instead of casting it to Integer you need to convert it to a string as shown above in order to output it the way you do.
If you need the total number of rows, you can use globalMap.get("tFileInputRegex_1_NB_LINE").toString() - but it is only available after the end of the loop, which means the component where you access it needs to be connected to tFileInputRegex_1 via OnSubjobOk trigger.
Related
I have two Coldfusion templates (getdata.cfm and generate.cfm). The first template getdata.cfm will retrieve from a database with a query, in addition to other tasks. It will retrieve exactly 16 rows of data and each row will have 8 fields. Such as this:
<cfquery datasource="xyz name="lista">
SELECT n1,n2,n3,n4,n5,n6,n7,n8
FROM atable
WHERE product = "abc"
ORDER BY date DESC LIMIT 16
</cfquery>
The second template will generate some random numbers and compare them against these 16 rows. There is a Refresh button on the second template to regenerate the numbers. This is how I would like it to work.
However, right now the only way for it to work is having the database <cfquery> in the second template, generate.cfm That means every time I press Refresh, it will access the database, retrieve the same 16 rows every time, and generate the random numbers. This is not ideal. Because the 16 rows are the same, it makes no sense to retrieve them every time a new set of random numbers get generated. It would be best to get them once, in the first template and somehow pass them to the second template. The 16 sets of numbers will need to be displayed on the screen at all times. The matched and unmatched numbers need to be shown.
How can I pass the whole query result from the first template to the second one without having to pass the 16 records as 16 lists via the form as form fields? Is this even possible? Thanks in advance.
Generate a set of random numbers.
Compare those numbers against a static set of data.
Repeat.
Do you need to do the comparison in the application (CFML) code? Can you generate the set of random numbers and send them to the DB as part of the query in a single request? That way, you get the records from the DB that match your set of numbers and not all 16.
Then every refresh would send the new set of random numbers to the DB, returning only the relevant data.
Alternately, you can use cfquery with the cachedWithin attribute in order to store the results of the query into memory for a specific amount of time while refreshing your random set of numbers.
https://cfdocs.org/cfquery
I have an excel sheet with many tabs. Say one is called wsMain and the other is called wsDate.
In my data flow transformation I am able to successfully load the data from wsMain to my table.
Now I have to update this transformation where I have to fetch the maximum date from the worksheet wsDate and only load data from wsMain where the date is less than on equal to the maximum date in wsDate (that is the only column available).
So for I have figured out that I need to create a new Excel connection manager to read the data from wsDate and I have used the Aggregate transformatioin to get the maximum date.
Now the question is how do I use this date to restrict the rows coming from wsMain?
I understand from the link below that you can store the value in a variable but what do I do next?:
SSIS set result set from data flow to variable
I have tried using a merge join but not sure if I am doing it right.
Here is what it looks like now:
I could not achieve the above but would be interested to know if that is possible. As a work around I have created a separate dataflow where I have stored the valued in a variable and then used the variable in the conditional split to filter the required rows:
Here is a step by step guide I followed to write the variable:
https://www.proteanit.com/2008/12/11/ssis-writing-to-a-package-variable-in-a-dataflow/
You can obtain the maximum value of the wsDate column first, this use this as a filter to avoid introducing unnecessary records into the data flow which which would be discarded by the Conditional Split. An overview of this process is below. I'd also recommend confirming the data types for all columns involved.
Create an SSIS DateTime variable and name this something descriptive such as MaxDate.
Create a Data Flow Task before the current one with an Excel Source component. Use the SQL command option for the Data Access Mode and enter a SQL statement to return the max value of the wsDate column. In the following example ExcelSource is the name of the sheet that you're pulling from. I'd suggested confirming the query with the Preview button on the Excel Source as well.
Add a Script Component (not Task) after the Excel Source. Add the MaxDate variable in the ReadWriteVariables field on the main page of the Script Component. On the Inputs and Outputs pane add the output column from the Excel Source as an Input Column with the ReadOnly usage Type. Example C# code for this is below. Note that variables can only be written to in the PostExecute method. The Input0_ProcessInputRow method is called once for each row that passes through, however there will only be the single row in this case. On the following code MaxExcelDate is the name of the output column from the Excel Source.
On the Excel Source component in the Data Flow Task where the records are imported from Excel, change the Data Access Mode to SQL command and enter a SQL statement to return records that have a date less than or equal to the maximum wsDate value. This is the last example and the ? is a placeholder for the parameter. After entering this SQL, click the Parameters button and select Parameter0 for the Parameters field, the MaxDate variable for Variables field, and a direction of Input. The Conditional Split can then be removed since these records will now be filtered out.
Excel MAX wsDate SELECT:
SELECT MAX(wsDate) AS MaxExcelDate FROM ExcelSource
C# Script Component:
DateTime maxDate;
public override void PostExecute()
{
base.PostExecute();
Variables.MaxDate = maxDate;
}
public override void Input0_ProcessInputRow(Input0Buffer Row)
{
maxDate = Row.MaxExcelDate;
}
Excel Command with Date Filter:
SELECT
Column1,
Column2,
Column3
FROM ExcelSheet
WHERE DateColumn <= ?
Yes, it is possible. In the data flow, you will need to determine the max date, which you already have. Next, you will need to MERGE JOIN the two data flows on the date column. From there, you will feed it into a CONDITIONAL SPLIT and split where the date columns match [i.e., !ISNULL()] versus do not match [i.e., ISNULL()]. In your case, you only want the matches. The non-matches will be disregarded.
Note: if you use an INNER JOIN on the MERGE JOIN where there is only one date (i.e., MaxDate) to join on, then this will take care of the row filtering for you. You will not need a CONDITIONAL SPLIT.
Welcome to ETL.
Update
It is a real pain that SSIS's MERGE JOINs only perform joins on EQUAL operations as opposed to LESS THAN and GREATER THAN operations. You will need to separate the data flows.
Use a script component to scan the excel file for the MAX Date and assign that value to a package variable in SSIS. Alternatively, you can have a dates table in SQL Server and then use an Execute SQL Command in SSIS to retrieve the MAX Date from the table and assign that value to a package variable
Modify your existing data flow to remove the reading of the Excel date file completely. Then add a DERIVED COLUMN transformation and add a new column that is mapped to the package variable in SSIS that stores the MAX date. You can name the Derived Column Name 'MaxDate'
Add a conditional split transformation with the following CONDITION logic: [AsOfDt] <= [MaxDate]
Set the Output Name to Insert Records
Note: The CONDITIONAL SPLIT creates a new output data flow with restricted/filtered rows. It does not create a new column within the existing data flow. Think of this as a transposition of data flow output from column modification to row modification. Only those rows that match the condition will be sent to the output that you desire. I assume you only want to Insert these records, so I named it that. You can choose whatever naming convention you prefer
Note 2: Sorry for not making the Update my original answer - I haven't used the AGGREGATE transformation before so I was not aware that it restricts row output as opposed to reading a value in the data flow and then assigning it to a variable. That would be a terrific transformation for Microsoft to add to SSIS. It appears that the ROWCOUNT and SCRIPT COMPONENT transformations are the only ones that have the ability to set a package variable value within the data flow.
Is there a way for me to know if the stream of rows has ended? That is, if the job is on the last row?
What im trying to do is for every 10 rows do something, my problem are the last rows, for example in 115 rows, the last 5 wont happen but i need them to.
There is no built-in functionality in Talend which tells you if you're on the last row. You can work around this using one of the following:
Get the row count beforehand. For instance, if you have a file, you
can use tFileRowCount to count the number of rows, then when you
process your file, you use a variable for your current row
number, and so you can tell if you've reached the last row. If your
data come from a database, you could either issue a query that
returns the total number of rows beforehand, or modify your main
query to return the total number of rows in an additional column and
use that (using ranking functions).
Do some processing after the subjob has ended: There may be situations
where you need a special processing for the last row, you can achieve
this by getting the last row processed by the previous subjob (which
you have already saved, for instance, by putting a tSetGlobalVar
after your target, when your subjob is done, your variable contains the last written value).
Edit
For your use case, what you could do is first store the result of the API call in memory using tHashOutput, then read it with a tHashInput in order to process it, and you'll know then how many rows you have retrieved using tHashOutput's global variable tHashOuput_X_NB_LINE.
I want row count which is mentioned in the image, to be used in my expression. How can I access it?
Image is here:
As mentioned in the documentation, there are several available variables. It depends on the place where you want to use the variable if it is already filled. This is from the aforementioned page:
NB_LINE: the number of rows processed. This is an After variable and it returns an integer.
So in your case this would be
((Integer) globalMap.get("tFileInputDelimited_2_NB_LINE"))
Talend also offers those variables in component input fields if you press Ctrl + Space.
Having some problems in a job, and I suspect it is due to a lack of understanding of tJavaFlex. I am generating 10 rows in this test job, and am generating loop inside a tJavaFlex:
So there are 10 rows coming in, and a loop in the Start and End section. I was expecting that for each row coming in, it would generate 10 identical rows coming out. And that I would see iterations 0,1,2,3....9 for each row.
What I got was this. This looks to me like the entire job is running 10 times, and so I have 100 random values coming through the flow from the tRowGenerator.
If I move the for loop into the Main Code section, I get close to the behaviour I was expecting. I am expecting each row when it comes in to be repeated 10 times, and for 1 row coming in to produce 10 output rows. What I get is this.
But even then my tLogRow is only generating one row for each 10 iterations it seems (look at the tLogRow output after iteration 9 above why not 10 items?). I had thought I would be getting 10 rows for each single row coming in and I would see this in the tLogRow.
What I need to do is take a value from a field coming in, do some reg exp parsing and split into an array, and then for each item in the array create lines in the output flow. i.e. 1 row coming in can be turned into x number of rows coming out using a string.split() method.
Can someone explain the behaviour above, and also advise on the best approach to get one value coming in, do some java manipulation and then generate multiple rows coming out?
Any advice appreciated.
Yes you don't use it correctly.
The initial part is for initiate variable. (executed one time before the first tow)
In the principal you put your loop (executed one time at each row)
In the final you store in global variable for example.(executed one time after the last row)
The principal code will be executed at each row in a tjavaflex. So don't put a for loop inside you can do like the example in the screen.
You tjavaflex comportement is normal. you have ten row so each row the for loop wil be executed 10 time (i<10)
You can use it like :
You dont need to create your own loop.
By putting the for loop in the Start code, your main code will be triggered by the loop and by incoming rows, and it will be executed n*r times.
The behaviour of subjob that contains a tJavaFlex, reveils that component before tJavaFlex is included into its starting code, and the after component is included in the ending code, but that may depend to many conditions like data propagation and trigger type.
start code :
System.out.print("tJavaFlex is starting...");
int i = 0;
Main code :
i++;
System.out.print("tJavaFlex inside Main Code...iteration:"+i);
row8.ITEM_NAME = row7.ITEM_NAME;
row8.ITEM_COUNT = row7.ITEM_COUNT;
End code :
System.out.print("tJavaFlex is ending...");
System.out.print(row7.ITEM_NAME);
Instead of main flow in row5, try using iterate flow to connect tJavaFlex