Similarities and differences between a tJoin and a tMap component?

tMap

author
Talend Documentation Team
EnrichVersion
6.4
EnrichProdName
Talend MDM Platform
Talend Open Studio for MDM
Talend Real-Time Big Data Platform
Talend Data Management Platform
Talend Open Studio for ESB
Talend Data Fabric
Talend Big Data
Talend Data Services Platform
Talend ESB
Talend Data Integration
Talend Open Studio for Data Integration
Talend Big Data Platform
Talend Open Studio for Big Data
task
Data Governance > Third-party systems > Processing components (Integration) > tMap
Design and Development > Third-party systems > Processing components (Integration) > tMap
Data Quality and Preparation > Third-party systems > Processing components (Integration) > tMap
EnrichPlatform
Talend Studio

tJoin or tMap can both be used to create a join between different data sources. However, tJoin is a basic component only used to create a join between two data sources while tMap has other properties designed for different needs.

You can find the differences between tJoin and tMap in the table below:
tJoin characteristics tMap specific characteristics
Main and a reject output flow Multiple output flows
Exact match between the keys of an expression Expression in the columns while providing the joining condition
Support of one match model Support of multiple match models (Unique match, First match and All matches)
Support of one look-up flow Support of various look-up flows and can load multiple look-up flows in parallel
  Storage of the look-up data on disk
  Reloading of the look-up data for each main record
  Supports of the 'die on error' option.

For more technologies supported by Talend, see Talend components.

Note: tMap is an advanced component that can be used in more complicated cases than tJoin. However, tMap generates more code while compiling and may take more space and time to load data into the memory during the Job execution. Generally speaking, use tJoin if it suits your needs. Otherwise, use tMap.

For further information, see The differences between Unique match, First match and All matches.