Extended Data Types

An Extended Data Type (EDT) is an AOT object that extends one of the system's primitive data types (string, integer, real, date, etc.) with additional metadata: labels, help text, string sizes, formatting rules, and relations. EDTs are the standard mechanism for defining reusable, semantically meaningful data types across the entire application.

Every table field, form control, method parameter, and variable in D365 F&O should reference an EDT rather than a raw primitive type. This ensures consistent labels, validation, formatting, and lookup behaviour wherever the same concept appears.

---

Primitive Data Types

D365 F&O provides the following primitive (base) data types. Each EDT must ultimately derive from one of these:

Primitive Type	X++ Type	SQL Type	Description
String	str	nvarchar(n)	Variable-length Unicode text. Size controlled by StringSize.
Integer	int	int	32-bit signed integer.
Int64	int64	bigint	64-bit signed integer. Used for RecId and large counters.
Real	real	numeric(p,s)	Fixed-point decimal. Scale controlled by Scale and NoOfDecimals.
Date	date	date	Calendar date without time component.
Time	timeOfDay	int	Time of day stored as seconds since midnight (0–86399).
UtcDateTime	utcdatetime	datetime2	Date and time in UTC. The runtime converts to/from user time zones.
Enum	enum	int	Integer value backed by a base enumeration.
Container	container	varbinary(max)	Binary-serialised X++ container. Not searchable or indexable.
Guid	guid	uniqueidentifier	128-bit globally unique identifier.

---

EDT Inheritance

One of the most important features of EDTs is inheritance. An EDT can extend another EDT using the Extends property, forming a parent–child chain. The child EDT inherits all properties from its parent and can override any of them.

How Inheritance Works

• When you set the Extends property on an EDT to the name of another EDT, the child inherits all of the parent's settings: label, help text, string size, relations, formatting, and display properties.
• The child can override any inherited property by setting it explicitly. Properties left at their default inherit from the parent at runtime.
• Inheritance chains can be multiple levels deep (e.g., AccountNum → CustAccount → CustVendAccount).
• The base type (string, int, real, etc.) is determined by the root EDT in the chain and cannot be changed by child EDTs.

See Code Examples for inheritance patterns in X++.

EnforceHierarchy

The EnforceHierarchy property controls whether the compiler enforces type safety across the EDT inheritance hierarchy:

• EnforceHierarchy = Yes — assignments and comparisons between EDTs must respect the hierarchy. You cannot assign a VendAccount to a CustAccount variable even though both extend AccountNum, because they are sibling types.
• EnforceHierarchy = No (default) — the compiler treats all EDTs of the same primitive base type as interchangeable (legacy behaviour).

tip

Microsoft best practice: set EnforceHierarchy = Yes on new EDT hierarchies. This catches type-mismatch bugs at compile time rather than producing silent data errors at runtime.

---

Creating an EDT

To create a new EDT in Visual Studio:

1. Right-click your project → Add → New Item → EDT String (or EDT Integer, EDT Real, etc.).
2. Set the Name property (PascalCase, e.g., CustAccount, TransDate, AmountMST).
3. Set Label and HelpText using label IDs for translation support.
4. Optionally set Extends to inherit from an existing EDT.
5. Set type-specific properties (e.g., StringSize for strings, NoOfDecimals for reals).
6. Add Relations or set ReferenceTable if the EDT should carry a default foreign-key relationship.

See Code Examples for variable declaration and method signature patterns.

---

Properties

The property table below shows all properties available on an EDT. The base properties (from AxEdt) are common to all EDT types. Type-specific properties are shown in separate colour-coded sections for each primitive type that adds its own properties.

59/59 properties

Property	Display Name	Type	Description
Common (all EDTs)
Name	Name	String	The name of the element.
Label	Label	String	Descriptive label visible to users on forms, reports, and Reporting tools.
HelpText	Help Text	String	Descriptive help text for the field, visible to users browsing the model via Reporting tools.
Extends	Extends	String	The parent EDT this type inherits from. All properties are inherited and can be overridden.
CollectionLabel	Collection Label	String	Label used when the plural name of an item stored with this type is needed.
ConfigurationKey	Configuration Key	String	The configuration key assigned to the item. Controls visibility based on licence configuration.
ReferenceTable	Reference Table	String	The table referenced by this EDT. Indicates the primary key table which this EDT references.
FormHelp	Form Help	String	The form to use when a lookup is performed from a field using this EDT.
DisplayLength	Display Length	Int32	Length of the display field, in number of characters.
ButtonImage	Button Image	ButtonImage	Alternative lookup button icon. Values: Arrow (0), Mail (1), URL (2), ThreeDots (3), OpenFile (4), Calendar (5), Phone (6), RightArrow (7).
Alignment	Alignment	Alignment_ITxt	Text alignment in the control. Values: Auto (0), Left (1), Right (2), Center (3).
Direction	Direction	Direction	Directional flow of characters when rendered. Values: Auto (0), LTR (1), RTL (2).
ControlClass	Control Class	String	The control class to use when a field using this EDT is added to a form.
PresenceIndicatorAllowed	Presence Indicator Allowed	NoYes	Whether the system should attempt to display a presence indicator. Values: No (0), Yes (1).
PresenceClass	Presence Class	String	X++ class used with PresenceMethod to return a PresenceInfo object instance.
PresenceMethod	Presence Method	String	Static method in PresenceClass called with the control's data value.
DataInteractorFactory	DataInteractorFactory Class	String	X++ class extending DataInteractorFactory for contextual data entry, lookups, and validation.
EnforceHierarchy	Enforce Hierarchy	NoYes	Whether assignments and comparisons must respect the EDT hierarchy. Values: No (0), Yes (1).
Literals	Literals	SqlLiteralMode_ITxt	How literals are represented in SQL statements. Values: Default (0), ForceLiterals (1), ForcePlaceholders (2).
CountryRegionCodes	Country Region Codes	String	Comma-separated list of country/region codes where this EDT is shown.
IsObsolete	Is Obsolete	NoYes	Whether the element is deprecated. Values: No (0), Yes (1).
Visibility	Visibility	CompilerVisibility	Compiler visibility level. Values: Private (0), Protected (1), Public (2), Internal (3), InternalProtected (4).
Tags	Tags	String	Tags for this element, separated by semicolons.
String
StringSize	String Size	Int32	Maximum number of characters allowed.
DatabaseStringSize	Database String Size	Int32	Maximum size of the string in the database. Can be larger than StringSize to allow extension in child EDTs.
StringSizeIsExtensible	String Size is Extensible	AutoNoYes	Whether the string size property is extensible on this EDT and child EDTs. Values: No (0), Yes (1), Auto (99).
DisplayHeight	Display Height	Int32	Fixed height value. For input controls, use with MultiLine to indicate a multi-line input.
Adjustment	Adjustment	Adjustment	Whether characters in fixed-length strings are stored on the left or right of the padding spaces. Values: Left (0), Right (1).
ChangeCase	Change Case	ChangeCase	Whether the system enforces the case of entered text. Values: Auto (0), None (1), UpperCase (2), LowerCase (3), SentenceCase (4).
Integer / Int64
AllowNegative	Allow Negative	AutoNoYes	Whether the control supports negative numbers. Values: No (0), Yes (1), Auto (99).
SignDisplay	Sign Display	SignDisplay	How the negative sign is displayed. Values: None (1), Prefixed (2), Suffixed (3), Parentheses (4), Auto (99).
ShowZero	Show Zero	AutoNoYes	Whether a numeric control shows zero or an empty field. Values: No (0), Yes (1), Auto (99).
RotateSign	Rotate Sign	AutoNoYes	Whether the value is negated for display (e.g., changes − to + and vice versa). Values: No (0), Yes (1), Auto (99).
DisplaceNegative	Displace Negative	Int32	Number of characters a negative number should indent to the right.
Real
NoOfDecimals	No Of Decimals	Int32	Number of decimal places stored and displayed for this data type.
NoOfDecimalsIsExtensible	No Of Decimals is Extensible	Boolean	Whether the number of decimals supports extension.
Scale	Scale	Int32	Scale value for SQL numeric precision.
DecimalSeparator	Decimal Separator	DecimalSeparator	Decimal separator character. Values: Dot (1), Comma (2), Auto (99).
ThousandSeparator	Thousand Separator	ThousandSeparator	Thousands separator character. Values: None (0), Dot (1), Comma (2), Apostrophe (3), Space (4), Auto (99).
AllowNegative	Allow Negative	AutoNoYes	Whether the control supports negative numbers. Values: No (0), Yes (1), Auto (99).
SignDisplay	Sign Display	SignDisplay	How the negative sign is displayed. Values: None (1), Prefixed (2), Suffixed (3), Parentheses (4), Auto (99).
ShowZero	Show Zero	AutoNoYes	Whether a numeric control shows zero or an empty field. Values: No (0), Yes (1), Auto (99).
RotateSign	Rotate Sign	AutoNoYes	Whether the value is negated for display. Values: No (0), Yes (1), Auto (99).
DisplaceNegative	Displace Negative	Int32	Number of characters a negative number should indent to the right.
FormatMST	Format MST	AutoNoYes	Whether the value is formatted as currency. Values: No (0), Yes (1), Auto (99).
AutoInsSeparator	Auto Ins Separator	AutoNoYes	Whether a decimal separator is inserted automatically. Values: No (0), Yes (1), Auto (99).
Date
DateFormat	Date Format	DateFormat_ITxt	Order in which day, month, and year are displayed. Values: Auto (0), YMD (1), YDM (2), MYD (3), DYM (4), MDY (5), DMY (6).
DateDay	Date Day	DateDay	How the day value is displayed. Values: None (0), Digits1or2 (1), Digits2 (2), Auto (99).
DateMonth	Date Month	DateMonth	How the month value is displayed. Values: None (0), Digits1or2 (1), Digits2 (2), Short (3), Long (4), Auto (99).
DateYear	Date Year	DateYear	How the year value is displayed. Values: None (0), Digits2 (2), Digits4 (4), Auto (99).
DateSeparator	Date Separator	DateSeparator_ITxt	Separator between year, month, and day values. Values include combinations of Slash, Dash, Dot, Space, None, and ChineseFormal (0–26).
MaxDateLabel	Max Date Label	String	Text displayed when the value exceeds the maximum date value.
Time
TimeFormat	Time Format	TimeFormat	Default time format. Values: Hour24 (1), AMPM (2), Auto (99).
TimeHours	Time Hours	AutoNoYes	Whether hours are shown. Values: No (0), Yes (1), Auto (99).
TimeMinute	Time Minute	AutoNoYes	Whether minutes are shown. Values: No (0), Yes (1), Auto (99).
TimeSeconds	Time Seconds	AutoNoYes	Whether seconds are shown. Values: No (0), Yes (1), Auto (99).
TimeSeparator	Time Separator	TimeSeparator	Separator between hours, minutes, and seconds. Values: Colon (1), Dot (2), Space (3), Comma (4), Slash (5), Auto (99).
Enum
EnumType	Enum Type	String	The base enumeration whose values are shown in the control.
Style	Style	Style_ITxt	Control display style. Values: Auto (0), Combobox (1), Radiobutton (2).

note

UtcDateTime EDTs inherit both Date and Time properties listed above, plus a TimezonePreference property: User (1), NoConversion (2), Auto (99). Guid and Container EDTs have no type-specific properties beyond the common set.

---

Child Objects

Every EDT can contain the following child objects:

Relations (AxEdtRelation)

EDT-level relations define a default foreign-key relationship. When a table field uses this EDT, the relation is automatically available unless the field sets IgnoreEDTRelation = Yes.

Property	Display Name	Type	Description
Tags	Tags	String	Tags for this element, separated by semicolons.
Table	Table	String	The related table for this relation.
RelatedField	Related Field	String	The field in the related table that this EDT maps to.

AxEdtRelationFixed extends AxEdtRelation with an additional property:

Property	Display Name	Type	Description
Value	Value	Int32	A fixed value used as a constant constraint in the relation.

Table References (AxEdtTableReference)

Table references provide an alternative way to define relationships, typically used with the ReferenceTable property for surrogate-key (RecId-based) relationships.

Property	Display Name	Type	Description
Tags	Tags	String	Tags for this element, separated by semicolons.
Table	Table	String	The reference table for the field.
RelatedField	Related Field	String	The field to relate to in the reference table.

AxEdtTableReferenceFilter extends AxEdtTableReference with an additional property:

Property	Display Name	Type	Description
Value	Value	Int32	A fixed filter value applied to the table reference.

Array Elements (AxEdtArrayElement)

Array elements allow an EDT to define multiple indexed values stored in separate database columns (a legacy feature from earlier AX versions, rarely used in D365 F&O).

Property	Display Name	Type	Description
Name	Name	String	The name of the element.
Label	Label	String	Label for this array element.
CollectionLabel	Collection Label	String	Plural label for this array element.
HelpText	Help Text	String	Help text for the array element.
Index	Index	Int32	The array index.
Tags	Tags	String	Tags for this element, separated by semicolons.

Each array element can also contain its own Relations and TableReferences child objects.