IndicesAttribute Class

Specifies the properties that participate in creation of non-unique database indices.

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v18.2.dll

Declaration

C#

[AttributeUsage(AttributeTargets.Class, Inherited = true)]
public sealed class IndicesAttribute :
    Attribute

VB.NET

<AttributeUsage(AttributeTargets.Class, Inherited:=True)>
Public NotInheritable Class IndicesAttribute
    Inherits Attribute

Remarks

Apply this attribute to a persistent class to specify database indices to be created in the database table associated with the class. Unlike IndexedAttribute, IndicesAttribute allows you to specify several non-unique indices for the current table using a single attribute declaration. The following code snippet illustrates usage of both attributes.

C#

[Indices("Name", "Name;Age", "Age;ChildCount")]
public class Person : XPObject {
    [Size(32)]
    public String Name;
    [Indexed(Unique = true), Size(64)]
    public String FullName;
    public int Age;
    public int ChildCount;
}

VB.NET

<Indices("Name", "Name;Age", "Age;ChildCount")> _
Public Class [Person]
    Inherits XPObject
    <Size(32)> _
    Public Name As String
    <Indexed(Unique := True), Size(64)> _
    Public FullName As String
    Public Age As Integer
    Public ChildCount As Integer
End Class

With this code in place, the database table corresponding to Person will have four indices.

1. A non-unique index over the Name column.
2. A non-unique multi-column index over the Name and Age columns.
3. A non-unique multi-column index over the Age and ChildCount columns.
4. A unique index over the FullName column.

Note

XPO does not support tables with multi-column (compound) keys or indexes in ASE databases. To avoid exceptions when connecting to ASE databases containing these tables, use one-column keys or indexes.

Inheritance

Object

Attribute

IndicesAttribute