Friday, January 9, 2015

Read XML with Optional Elements

This post I will describe how to parse XML with optional element.

We will use below source xml file which has three customer details, along with awards details, and <CUSTOMERAWARDS> is a optional xml element.

Sample XML file
Sample XML File

We will parse this file using tXMLMap component. so fist of all add tFileInputXML and configure as below.

  • Assign source file path

  • Create single column in schema named as

  • Create CUSTOMERS column with "Document" data type in schema.

  • Put loop Xpath query = "/CUSTOMERS"

  • In Mapping section add XPath Query ="."

  • Select Get Nodes check box.

Add tXMLMap component and connect with tFileInputXML component using Main link and create source tree structure as shown in image.
Note: You can create create sub elements manually or  it can be  populated from XSD file or from repository.

Add two Outputs and drag and drop relevant source columns to output (Refer image).



tXMLMap Configuration
tXMLMap Configuration

Click on first output`s "set loop function" short menu and add one sequence then select xpath = customerid xpath, see the image for more details.


tXml Map First Output
tXml Map First Output

Our first Output is ready now you have to configure second output so follow the steps we did for first output and select xpath= customerawards, see the image for more details.



tXml Map Second Output
tXml Map Second Output

Add tlogrow for each output and then execute the job you will see output like below. If you observe, customer id 1236 it has no awards extracted but customer id 1234 and 1235 awards extracted completely.



OutPut
Out Put

Difference between tMap and tJoin

tMap is frequently used component for joins and lookup purpose, it is also use for verity of operations and transformations, whereas tJoin is used for join and look-ups only.


tMap


tJoin


It accepts more than one input one is main and rests of the lookups.


It accepts only two inputs and only one is main and other one is lookup.


We can create more than one output


It has two default outputs one is "Main" and another one is " Inner join reject"


tMap has "inner join " and " left outer join" joining model


tJoin offer`s only "inner join"


tMap offers three match model


  1. Unique Match
  2. First Match
  3. All Matches


tJoin defaulted with Unique match


tMap allows to store data on file option for lookup data processing


tJoin doesn`t offer this feature


In tMap you can filter data using filter expression


tJoin doesn`t offer this feature


You can write transformation using expression builder at each column level


tJoin doesn`t offer this feature

Split Rows to Columns

This post I will describe you how to split rows into columns, we will use below sample as input records.

Input Rows.

Input Rows
Input Rows

Expected Output.

out put
Out Put

Create a Job and add tFixedFlowInput component and  put above input as "Use inline content" and create schema as shown in image.

Input Schema
Input Schema

Add tPivotToColumnsDelimited  component and connect with tFixedFlowInput component as main connection then configured this component shown in below image.

tPivot component Configuration
tPivot component Configuration

Configurations :

Pivot Column ="Type"

Aggregation column="Value"

Aggregation Function ="last"

Group by "ID" and "Name" column.

Rest of the configuration is for output file, where our output will be transferred. to read output file we can use either delimited component but for quick review I`ll use tFileInputFullRow.

Add tFileInputFullRow below the tFixedFlowInput component and connect with "On Sub Job Ok" trigger. and provide previously created file path and rest of the details.

add tLogRow and connect to tFileInputFullRow component and execute the job you will get above out put on console.

Final Job Design.

Job with OutPut
Job with OutPut

This component will create N number of columns based on your input, if you are dealing with fix schema then it will create complexity for further processing.

Thursday, January 1, 2015

Split large XML into multiple XML

In this post, I will describe you how to split large XML into several xml.

Here is our Sample XML file. ( which is not huge but just a sample)

Split Xml Talend

We are expecting three XML files from sample xml hence lets start with metadata creation for this sample file.

Once you created metadata then you can drag and drop schema to job designer. for the scenario we will choose tFileInputXML component.

Now add another component tXMLMap and link tFileInputXML to tAdvancedFileOutputXml then configure tAdvancedFileOutputXml as shown in image.

tAdvanceOutputXMl Mapping

Now we have mapped our source column to output columns, but it will output all the rows in single file, to create a file for each row we have to configured tAdvancedFileOutputXML component using Advance property of component tab. use "Spit output in Several files" option with value as "1". by doing this it will create new file for each row.

tAdvancedOutputXML Setting

After run, this job will create three files on mention path like below.

Output Xml Files

And here is the final output.

Output Xml Files splitxml6 splitxml7

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