Similarities and differences between a tJoin and a tMap component?
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. |
Information noteNote: 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.
For further information, see The differences between Unique match, First match and All matches on Talend Help Center (https://help.talend.com).