SqlHierarchyId 结构

语法

声明
<SqlUserDefinedTypeAttribute(Format.UserDefined, IsByteOrdered := True,  _
    MaxByteSize := , Name := "SqlHierarchyId")> _
<CLSCompliantAttribute(True)> _
Public Structure SqlHierarchyId _
    Implements IBinarySerialize, INullable, IComparable
用法
Dim instance As SqlHierarchyId

[SqlUserDefinedTypeAttribute(Format.UserDefined, IsByteOrdered = true, 
    MaxByteSize = , Name = "SqlHierarchyId")]
[CLSCompliantAttribute(true)]
public struct SqlHierarchyId : IBinarySerialize, 
    INullable, IComparable

[SqlUserDefinedTypeAttribute(Format::UserDefined, IsByteOrdered = true, 
    MaxByteSize = , Name = L"SqlHierarchyId")]
[CLSCompliantAttribute(true)]
public value class SqlHierarchyId : IBinarySerialize, 
    INullable, IComparable

[<SealedAttribute>]
[<SqlUserDefinedTypeAttribute(Format.UserDefined, IsByteOrdered = true, 
    MaxByteSize = , Name = "SqlHierarchyId")>]
[<CLSCompliantAttribute(true)>]
type SqlHierarchyId =  
    struct
        interface IBinarySerialize
        interface INullable
        interface IComparable
    end

JScript 支持使用结构，但不支持声明新结构。

属性

	名称	说明
	IsNull	Gets a value indicating whether the SqlHierarchyId is nullNothingnullptrunitnull 引用（在 Visual Basic 中为 Nothing）.
	Null	Gets a SqlHierarchyId with a hierarchy identification of nullNothingnullptrunitnull 引用（在 Visual Basic 中为 Nothing）.

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方法

	名称	说明
	CompareTo(Object)	Returns a value indicating the results of a comparison between a SqlHierarchyId and an object.
	CompareTo(SqlHierarchyId)	Returns a value indicating the results of a comparison between two SqlHierarchyId nodes.
	Equals	Evaluates whether SqlHierarchyId and obj are equal. （覆盖 ValueType. . :: . .Equals(Object)。）
	Finalize	（从 Object 继承。）
	GetAncestor	Retrieves the SqlHierarchyId node n levels up the hierarchical tree.
	GetDescendant	Gets the value of a descendant SqlHierarchyId node that is greater than child1 and less than child2.
	GetHashCode	Gets a hash of the path from the root node of the hierarchy tree to the SqlHierarchyId node. （覆盖 ValueType. . :: . .GetHashCode() () () ()。）
	GetLevel	Gets a value indicating the level of the SqlHierarchyId node in the hierarchical tree.
	GetReparentedValue	Gets a value representing the ___location of a new SqlHierarchyId node that has a path from newRoot equal to the path from oldRoot to this, effectively moving this to the new ___location.
	GetRoot	Gets a value representing the root SqlHierarchyId node of the hierarchy.
	GetType	（从 Object 继承。）
	IsDescendantOf	Gets a value indicating whether the SqlHierarchyId node is the descendant of the parent.
	MemberwiseClone	（从 Object 继承。）
	Parse	Converts the canonical string representation of a SqlHierarchyId node to a SqlHierarchyId value.
	Read	Reads from a specified binary reader into a SqlHierarchyId.
	ToString	Returns the canonical string representation of a SqlHierarchyId node from a SqlHierarchyId value. （覆盖 ValueType. . :: . .ToString() () () ()。）
	Write	Writes a SqlHierarchyId to a specified binary writer.

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运算符

	名称	说明
	Equality	Evaluates whether two SqlHierarchyId nodes are equal.
	GreaterThan	Evaluates whether one specified SqlHierarchyId node is greater than another.
	GreaterThanOrEqual	Evaluates whether one specified SqlHierarchyId node is greater than or equal to another.
	Inequality	Evaluates whether two SqlHierarchyId nodes are unequal.
	LessThan	Evaluates whether one specified SqlHierarchyId node is less than another.
	LessThanOrEqual	Evaluates whether one specified SqlHierarchyId node is less than or equal to another.

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注释

This type provides the following benefits for storing hierarchical information:

• Very compact data storage.

• Depth-first comparison. Indexes on this type are in depth-first order, and nodes close to each other in a depth-first traversal are stored near each other.

• Support for arbitrary insertions and deletions.

• A limitation of this type is that a single instance of the hierarchy data type can be no larger than 892 bytes. Hierarchies that possess too many levels to fit within this limitation must use a different data type.

The HierarchyId type is available to CLR clients as the SqlHierarchyId data type.

示例

DECLARE @employee hierarchyid
SELECT @employee = OrgNode FROM HumanResources.EmployeeDemo
  WHERE LoginID = 'adventure-works\dylan0'

SELECT * FROM HumanResources.EmployeeDemo
WHERE @employee.IsDescendantOf(OrgNode) = 1

线程安全

此类型的任何公共 static（在 Visual Basic 中为 Shared） 成员都是线程安全的。不保证所有实例成员都是线程安全的。

请参阅

参考