Transformation
Manager (TM) is used to develop programs which transform data from one format to
another. TM can be used to transform data between any combination of relational,
Java or XML sources and targets using in-built adapters and to any kind of data
using TM Open Interfaces.
Transformation
Manager is meta-data driven but generates pure Java code. This code may be used
on any Java JM (1.3 and above) to perform data transformations.
From release 2.4 onwards it has been possible to run Transformation Manager in the 'short lived' or 'long lived' mode. The main difference is that in the 'short lived' mode TM objects are freshly created for particular transform, and then garbage collected, while in 'long lived' mode TM objects are allowed to persist in memory. When running in 'short lived' mode the principal TM class is called TMTransformer; in 'long lived' mode it is called TMTransformExecutor.
Historically Transformation Manager had been packaged for use in a stand-alone environment, and hence in 'short lived' mode. In this mode of operation a run-time interface TMTransformer object exists only for the lifetime of the transforms. This use of TM is well-documented in existing documentation and has its attractions. Where machine efficiency is not of paramount importance this type of short lived TMTransformer can be a very neat way of packaging transforms. However the big downside is that to create the TMTransformer object takes time - even when the transforms are packaged as Java. Where the transforms of packaged as XML (i.e. are supplied as XML meta descriptions) then this time increases still further.
For this reason ETL also provide a long lived component known as TMTransformExecutor. In addition TMTransformExecutor gives a more fine grained control over transform execution.
Note that both TMTransformer and TMTransformExecutor extends the common interface TMTransformerCommon, which thus contains many of the most important methods.
This guide begins by explaining the method by which Java Code is generated and then describes all aspects of deploying Java transforms generated by TM product at run-time and includes:
Note that the code examples included in this section are taken from the standard examples distributed with the product. Note that ALL possible combinations of source and target are legal - it is only for conciseness that this document limits the examples to the those described in the sections listed above. Thus it is quite legal to transform between XML and XML or between database and database.