AmendExpressionAttribute Class

Defines an attribute that will request amendment of a table name or field list with the specified text.

Inheritance Hierarchy

SystemObject
SystemAttribute
GSF.Data.ModelAmendExpressionAttribute

Namespace: GSF.Data.Model
Assembly: GSF.Core (in GSF.Core.dll) Version: 2.4.207-beta+1781b796b2aa7a54013a031eb432fe4ccee31867

Syntax

C++

JavaScript

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[AttributeUsageAttribute(AttributeTargets.Class, AllowMultiple = true)]
public sealed class AmendExpressionAttribute : Attribute

<AttributeUsageAttribute(AttributeTargets.Class, AllowMultiple := true)>
Public NotInheritable Class AmendExpressionAttribute
	Inherits Attribute

[AttributeUsageAttribute(AttributeTargets::Class, AllowMultiple = true)]
public ref class AmendExpressionAttribute sealed : public Attribute

[<SealedAttribute>]
[<AttributeUsageAttribute(AttributeTargets.Class, AllowMultiple = true)>]
type AmendExpressionAttribute = 
    class
        inherit Attribute
    end

GSF.Data.Model.AmendExpressionAttribute = function();

Type.createClass(
	'GSF.Data.Model.AmendExpressionAttribute',
	Attribute);

View Source

The AmendExpressionAttribute type exposes the following members.

Constructors

	Name	Description
	AmendExpressionAttribute(String)	Creates a new AmendExpressionAttribute that will request application of amendmentText for any database.
	AmendExpressionAttribute(String, DatabaseType)	Creates a new AmendExpressionAttribute that will request application of amendmentText for the specified targetDatabaseType.

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Properties

	Name	Description
	AffixPosition	Gets or sets location for amendment application; defaults to Suffix.
	AmendmentText	Gets or sets amendment text to be applied.
	StatementTypes	Gets or sets statement types for amendment application; defaults to Select.
	TargetDatabaseType	Gets target DatabaseType for amendment application.
	TargetExpression	Gets or sets target expression for amendment application; defaults to TableName.
	TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)

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Methods

	Name	Description
	Equals	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute)
	GetHashCode	Returns the hash code for this instance. (Inherited from Attribute)
	GetType	Gets the Type of the current instance. (Inherited from Object)
	IsDefaultAttribute	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute)
	Match	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
	ToString	Returns a string that represents the current object. (Inherited from Object)

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Extension Methods

	Name	Description
	GetEnumValueOrDefault	Gets the enumeration constant for value, if defined in the enumeration, or a default value. (Defined by EnumExtensions)
	GetEnumValueOrDefaultT	Gets the enumeration constant for this value, if defined in the enumeration, or a default value. (Defined by EnumExtensions)

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Remarks

As an example, this can be used to add table hints, e.g., WITH (NOLOCK), for select statements in SQL Server.

Applying the AmendExpressionAttribute to a modeled table with no specified database type parameter will be meant to infer that the amendment be used for all database types. Using a specific database type as a parameter to the attribute, e.g., [AmendExpression("WITH (NOLOCK)", DatabaseType.SQLServer)], means the amendment text will only be applied to the specific database - however, the attribute allows multiple instances on the same identifier so you could specify that amendment application only be applied to two databases:

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[AmendExpression("AS T1", DatabaseType.SQLServer), AmendExpression("AS T1", DatabaseType.MySQL)]

Other parameters exist to fully customize target expression, set affix position and specify statement types:

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[AmendExpression("TOP 200",
    TargetExpression = TargetExpression.FieldList,
    AffixPosition = AffixPosition.Prefix,
    StatementTypes = StatementTypes.SelectSet)]

Reference

GSF.Data.Model Namespace