Parameter Element (CSDL)
The Parameter element in conceptual schema definition language (CSDL) can be a child of the FunctionImport element or the Function element.
FunctionImport Element Application
A Parameter element (as a child of the FunctionImport element) is used to define input and output parameters for function imports that are declared in CSDL.
The Parameter element can have the following child elements (in the order listed):
Documentation (zero or one elements allowed)
Annotation elements (zero or more elements allowed)
Applicable Attributes
The following table describes the attributes that can be applied to the Parameter element.
| Attribute Name | Is Required | Value |
|---|---|---|
Name |
Yes |
The name of the parameter. |
Type |
Yes |
The parameter type. The value must be an EDMSimpleType or a complex type that is within the scope of the model. For more information, see Conceptual Model Types (CSDL). |
Mode |
No |
In, Out, or InOut depending on whether the parameter is an input, output, or input/output parameter. |
MaxLength |
No |
The maximum allowed length of the parameter. |
Precision |
No |
The precision of the parameter. |
Scale |
No |
The scale of the parameter. |
Note
Any number of annotation attributes (custom XML attributes) may be applied to the Parameter element. However, custom attributes may not belong to any XML namespace that is reserved for CSDL. The fully-qualified names for any two custom attributes cannot be the same.
Example
The following example shows a FunctionImport element with one Parameter child element. The function accepts one input parameter and returns a collection of entity types.
<FunctionImport Name="GetStudentGrades"
EntitySet="StudentGrade"
ReturnType="Collection(SchoolModel.StudentGrade)">
<Parameter Name="StudentID" Mode="In" Type="Int32" />
</FunctionImport>
Function Element Application
A Parameter element (as a child of the Function element) defines parameters for functions that are defined or declared in a conceptual model.
The Parameter element can have the following child elements (in the order listed):
Documentation (zero or one elements)
CollectionType (zero or one elements)
ReferenceType (zero or one elements)
RowType (zero or one elements)
Note
Only one of the CollectionType, ReferenceType, or RowType elements can be a child element of a Property element.
- Annotation elements (zero or more elements allowed)
Note
Annotation elements must appear after all other child elements. Annotation elements are only allowed in conceptual models for applications that target the .NET Framework version 4 or later. The XML namespace for such models is https://schemas.microsoft.com/ado/2008/09/edm.
Applicable Attributes
The following table describes the attributes that can be applied to the Parameter element.
| Attribute Name | Is Required | Value |
|---|---|---|
Name |
Yes |
The name of the parameter. |
Type |
No |
The parameter type. A parameter can be any of the following types (or collections of these types):
For more information about these types, see Conceptual Model Types (CSDL). |
Nullable |
No |
True (the default value) or False depending on whether the property can have a null value. |
DefaultValue |
No |
The default value of the property. |
MaxLength |
No |
The maximum length of the property value. |
FixedLength |
No |
True or False depending on whether the property value will be stored as a fixed length string. |
Precision |
No |
The precision of the property value. |
Scale |
No |
The scale of the property value. |
Unicode |
No |
True or False depending on whether the property value will be stored as a Unicode string. |
Collation |
No |
A string that specifies the collating sequence to be used in the data source. |
Note
Any number of annotation attributes (custom XML attributes) may be applied to the Parameter element. However, custom attributes may not belong to any XML namespace that is reserved for CSDL. The fully-qualified names for any two custom attributes cannot be the same.
Example
The following example shows a Function element that uses one Parameter child element to define a function parameter.
<Function Name="GetYearsEmployed" ReturnType="Edm.Int32">
<Parameter Name="Instructor" Type="SchoolModel.Person" />
<DefiningExpression>
Year(CurrentDateTime()) - Year(cast(Instructor.HireDate as DateTime))
</DefiningExpression>
</Function>
See Also
Concepts
Entity Framework Overview
CSDL Specification
EntityContainer Element (CSDL)
Other Resources
CSDL, SSDL, and MSL Specifications
ADO.NET Entity Data Model Tools
How to: Import a Stored Procedure
How to: Define Custom Functions in the Conceptual Model