Data Types

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1 Introduction

Throughout Studio Pro the same set of data types are used. The exception is the type of attributes, which is more specific with regard to storage in the database. In general, an attribute type maps to the data type with the same name. The exceptions are mentioned in the table below.

2 Data Types Supported

Mendix supports the following data types:

Name Description Examples
Boolean A truth value. true and false
Binary Binary data such as files and images.
Date and time A point in time consisting of a date and a time component accurate up to milliseconds. Thursday, 12 February 2015, 14:50:36
Decimal A high-precision fractional number. The Decimal type can be used for high-precision calculations. Use this type to represent amounts of money for example. A Decimal can have up to 20 digits before the decimal point, and up to 8 after. 3.14, 738000000000.00000001
Enumeration One of the values of the given enumeration. Red, Green, Blue; Todo, Running, Done
Integer/Long A whole number between -(2^63) and 2^63 - 1. The attribute types AutoNumber, Integer and Long map to this data type. -42, 0, 123
List A list of objects of a specific entity.
Nothing No value. Can only be used as the return type of a microflow.
Object A single object of a specific entity.
String A piece of text that can contain letters, numbers, spaces and other characters. The attribute types String and Hashed string both map to this data type. ‘Hello World!’; ‘Desiderius Erasmus’

If you want to change data from one type to another (for example, to display a number as part of a message in a text box) you will usually need to use an expression to do this. See Expressions for more information on what is available.

An exception is converting an Integer/Long to a Decimal, where conversion is done implicitly if you provide an Integer/Long where a Decimal is expected.