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 lookups only.



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

About Umesh

I am Software consultant with approx 7 years of experience mainly in Business Intelligence and data warehousing assignments using Talend. Writing is not my passion but i am doing it to help others. if you have any special case where you want me to demonstrate then please post me.

7 comments on “Difference between tMap and tJoin

  1. I am having an interview on Talend. Can you help me on the interview related questions . Also provide me the answers. Are the quests gonna me only theoritrical?

    1. Hi Swetha,

      you can find some the questions and their answers on respective question link. i would suggest try all examples from our site. you can face any kind of interview almost all the things covered.

  2. Hi Umesh,
    Thanks for your blog. One thing i would like to say that tJoin does do Full Join as well. It does that when you uncheck Inner Join Reject option. When saying this statement, i am referring to Talend version 5.5.

    Bharat Khanna

  3. Hi, can we use large XML file to convert into CSV file in Talend ? If so can we view the schema of XML file while creating the metadata ?/ While creating the metadata , I got the error message “Unhandled event loop exception java heap space error in talend” , why ????

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