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====== Data Operation - Concat ======


===== About =====

''Concat'' is a [[:docs:flow:intermediate|intermediate data operation]] that will concatenate multiple data resources into one.



It's an alias of the [[docs:op:transfer|transfer operation]] where:
  * the method is set to [[:docs:op:insert|insert]]
  * the target name stays the same for all sources (ie the [[docs:flow:template_data_uri|target data uri]] does not have a [[docs:flow:template_string|target pattern]] in its path)

===== Cli =====

The ''concat'' operation is also available via the [[:docs:tabul:data:concat|tabul data command]].
===== Note =====


==== What if the target exists ====

Note that the data operation is [[:docs:op:insert|insert]] therefore if the target resource exists, the data is appended.

==== Effect of metadata on file concatenation ====


Note that concatenating [[:docs:system:file|files]] that does not store any [[:docs:resource:metadata|metadata]] (such as [[:docs:resource:csv|csv file]] without ''header'') 
should be quicker.

Why ?

The concatenation is performed:
  * physically: ''block by block'' (bytes disk operation)
  * and not logically: [[:docs:resource:record|record by record]]