Class HierarchyAttribute

Hierarchy attribute

Inheritance
Object
Attribute
HierarchyAttribute
Inherited Members
Namespace: XData.Mapping
Assembly: XData.docfx.dll
Syntax
[AttributeUsage(AttributeTargets.Class, AllowMultiple = true)]
public sealed class HierarchyAttribute : Attribute
Remarks

Tables can be hierarchically liked to themselves.

On every hierarchical link is possible to build hierarchy table, to simplify tree structure queries.

It's alternative of ORACLE CONNECT BY PRIOR...START WITH construction for other database engines

// Table T_TEST has parent_id field tree linked to test_id (T_TEST's pk)


// Table L_TEST has two fields parent_id and child_id all linked to T_TEST.test_id 


// Table L_TEST contains all subtree relations inside T_TEST


// For example: for T_TEST (test_id, parent_id): (1, null) : (2, 1) : (3, 2)


// L_TEST will contain (parent_id, child_id): (1, 1) : (1, 2) : (1, 3) : (2, 2) : (2, 3) : (3, 3)


    [DataObject("T"),


        DataTable("T_TEST", "T"),


        Hierarchy("T", "L_TEST", "parent_id", "parent_id", "child_id"),


        Column("TestId", "test_id", typeof(long?), "T", Flags = DataPropertyFlag.Id)]

WARNING! Hierarchy base table (T_TEST in example above) mast contain non complex primary key!

Hint: Possible to describe multiple hierarchies across one table using different tree links

Constructors

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HierarchyAttribute(String, String, String, String, String)

Hierarchy attribute

Declaration
public HierarchyAttribute(string source, string treeTableName, string parent, string linkParent, string linkChild)
Parameters
Type Name Description
String source

Source table alias
String treeTableName

Link table name
String parent

Source table parent column name
String linkParent

Link table parent column name
String linkChild

Link table child column name
Exceptions
Type Condition
XDataRuntimeException

Source table alias cannot be null or empty string
XDataRuntimeException

Link table name cannot be null or empty string
XDataRuntimeException

Source table parent column name cannot be null or empty string
XDataRuntimeException

Link table parent column name cannot be null or empty string
XDataRuntimeException

Link table child column name cannot be null or empty string

Properties

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LinkChild

Link table child column name

Declaration
public string LinkChild { get; }
Property Value
Type Description
String
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LinkParent

Link table parent column name

Declaration
public string LinkParent { get; }
Property Value
Type Description
String
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Parent

Source table parent column name

Declaration
public string Parent { get; }
Property Value
Type Description
String
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Source

Source table alias

Declaration
public string Source { get; }
Property Value
Type Description
String
See Also
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TreeTableName

Link table name

Declaration
public string TreeTableName { get; }
Property Value
Type Description
String
Remarks

Tree table contains links from tree node to all subtree nodes.

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TypeId

When implemented in a derived class, gets a unique identifier for this Attribute.

Declaration
public override object TypeId { get; }
Property Value
Type Description
Object

An Object that is a unique identifier for the attribute.
Overrides

Extension Methods