.NET Framework 4.5.2+
.NET Framework 4.5.2+
.NET Standard 2.0+

IndicesAttribute Class

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

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v19.2.dll

Declaration

[AttributeUsage(AttributeTargets.Class, Inherited = true)]
public sealed class IndicesAttribute :
    Attribute
<AttributeUsage(AttributeTargets.Class, Inherited:=True)>
Public NotInheritable Class IndicesAttribute
    Inherits Attribute
[AttributeUsage(AttributeTargets.Class, Inherited = true)]
public sealed class IndicesAttribute :
    Attribute
<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.


[Indices("Name", "Name;Age", "Age;ChildCount")]
public class Person : XPObject {
    [Size(32)]
    public String Name {
        get { return fName; }
        set { SetPropertyValue(nameof(Name), ref fName, value); }
    }
    String fName;

    [Indexed(Unique = true), Size(64)]
    public String FullName {
        get { return fFullName; }
        set { SetPropertyValue(nameof(FullName), ref fFullName, value); }
    }
    String fFullName;

    public int Age {
        get { return fAge; }
        set { SetPropertyValue(nameof(Age), ref fAge, value); }
    }
    int fAge;

    public int ChildCount {
        get { return fChildCount; }
        set { SetPropertyValue(nameof(ChildCount), ref fChildCount, value); }
    }
    int fChildCount;

}

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
See Also