DML: data class

Data Class is a property that describes what kind of data can be stored in a Mapping Services object. When the Map Engine executes an integration task, it uses data class to check that the data in the relevant DML Block corresponds with the kind of values that were expected for those DML Blocks. This check ensures that the Map Engine has the appropriate data to complete integration processes.

In Mapping Services, you assign a data class to:

  • Business Document nodes
  • Function parameters
  • Function return values
  • Variables
  • Table columns

Constants in DML expressions also have a data class. When you define a Constant, you must respect the conventions for the relevant data class.

In Mapping Services, data classes are represented by their initial character (for example, B for Boolean). The following table introduces the data classes.

Data class Data characteristics


The result of a condition: true or false

Date and Time

A date and time

The maximum length of a date and time is 26 characters.


A whole number

The maximum length of an integer is 39 characters, including the positive or the negative sign (+,-).

Real Number

A rational number

The maximum length of:

  • The mantissa is 38 characters, including the decimal marker.
  • The exponent is 3 characters.


Alphanumeric characters

The maximum length of a string is usually 4,096 characters. However, in a Table column, strings cannot exceed 255 characters.

Very Large Object

Binary (multi-media) data

The maximum size of a very large object is 2 gigabytes. Examples include strings (longer than 4,096 characters), bitmaps, sound, or video files.

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